posts_gdocs: 1XtmzRJEsS8JPM-6JVzsXPRzAM2baoTwo669nB7A3Vr0

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id	slug	type	content	published	createdAt	publishedAt	updatedAt	publicationContext	revisionId	breadcrumbs	markdown	title
1XtmzRJEsS8JPM-6JVzsXPRzAM2baoTwo669nB7A3Vr0	conflict-data-how-do-researchers-measure-armed-conflicts-and-their-deaths	article	{ "toc": [ { "slug": "keep-reading-at-our-world-in-data", "text": "Keep reading at Our World in Data", "title": "Keep reading at Our World in Data", "supertitle": "", "isSubheading": false } ], "body": [ { "text": [ { "type": "text", "value": [ { "text": "Explore the data discussed in this article in our work on ", "spanType": "span-simple-text" }, { "url": "https://docs.google.com/document/d/1fdECw4wt6d7_-cIeMcsBfnoUEoeKwF2Z1gj3Y8RCF4g/edit", "children": [ { "text": "War and Peace", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": " and our ", "spanType": "span-simple-text" }, { "url": "https://docs.google.com/document/d/1SpyofFwtTSpD69fW6rUq-D-zM6DSsW7I7l0_bNC-AMA/edit", "children": [ { "text": "Conflict Data Explorers", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": ", and read more about its measures in ", "spanType": "span-simple-text" }, { "url": "https://docs.google.com/document/d/1H_dmh_1YYoY605lcVHtyOm2RZ2AfpIUuimG99ubmcHs/edit", "children": [ { "text": "our article on them", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": ".", "spanType": "span-simple-text" } ], "parseErrors": [] } ], "type": "callout", "title": "More on conflict data", "parseErrors": [] }, { "type": "text", "value": [ { "text": "Measuring armed conflicts and conflict deaths across the world helps us understand how people\u2019s lives and livelihoods are affected by large-scale violence.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "But this comes with many challenges. People do not always agree on what characteristics define an armed conflict. Even once defined, these characteristics \u2014 especially how many people died in them \u2014 are difficult to assess.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "The people affected are not always asked who has died around them due to the conflict.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "The conflict parties may underreport deaths to claim success, or overreport them to encourage intervention by third parties.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "Independent observers may also struggle to be present in all places and document a conflict\u2019s death toll.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "So how do researchers address these challenges?", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "In our work on ", "spanType": "span-simple-text" }, { "url": "https://ourworldindata.org/war-and-peace", "children": [ { "text": "War and Peace", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": ", we provide data from six sources that identify armed conflicts and count their deaths:", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "list", "items": [ { "type": "text", "value": [ { "text": "Uppsala Conflict Data Program (UCDP)", "spanType": "span-simple-text" }, { "url": "#note-1", "children": [ { "children": [ { "text": "1", "spanType": "span-simple-text" } ], "spanType": "span-superscript" } ], "spanType": "span-ref" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "Project Mars by Jason Lyall (2022)", "spanType": "span-simple-text" }, { "url": "#note-2", "children": [ { "children": [ { "text": "2", "spanType": "span-simple-text" } ], "spanType": "span-superscript" } ], "spanType": "span-ref" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "Militarized Interstate Events by Douglas Gibler and Steven Miller", "spanType": "span-simple-text" }, { "url": "#note-3", "children": [ { "children": [ { "text": "3", "spanType": "span-simple-text" } ], "spanType": "span-superscript" } ], "spanType": "span-ref" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "Correlates of War (CoW)", "spanType": "span-simple-text" }, { "url": "#note-4", "children": [ { "children": [ { "text": "4", "spanType": "span-simple-text" } ], "spanType": "span-superscript" } ], "spanType": "span-ref" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "Peace Research Institute Oslo (PRIO)", "spanType": "span-simple-text" }, { "url": "#note-5", "children": [ { "children": [ { "text": "5", "spanType": "span-simple-text" } ], "spanType": "span-superscript" } ], "spanType": "span-ref" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "Conflict Catalog by Peter Brecke (1999)", "spanType": "span-simple-text" }, { "url": "#note-6", "children": [ { "children": [ { "text": "6", "spanType": "span-simple-text" } ], "spanType": "span-superscript" } ], "spanType": "span-ref" } ], "parseErrors": [] } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "These sources all measure armed conflicts and their deaths; they cover many countries and years, and researchers and policymakers frequently use them.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "In our ", "spanType": "span-simple-text" }, { "url": "https://docs.google.com/document/d/1SpyofFwtTSpD69fW6rUq-D-zM6DSsW7I7l0_bNC-AMA/edit", "children": [ { "text": "Conflict Data Explorers", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": ", you can delve into global and regional overviews of conflicts and their deaths.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "Reassuringly, sources typically agree about big differences in the deaths from armed conflicts: they readily distinguish between deadly and peaceful years.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "But they do not always agree. They often come to different assessments about ", "spanType": "span-simple-text" }, { "children": [ { "text": "how ", "spanType": "span-simple-text" } ], "spanType": "span-italic" }, { "text": "widespread and deadly some years were.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "Why do these sources arrive at different numbers? And is there any best approach?", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "I summarize the key similarities and differences between the different approaches in this article and when to use which one.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "text": [ { "text": "What conflicts are covered?", "spanType": "span-simple-text" } ], "type": "heading", "level": 1, "parseErrors": [] }, { "type": "text", "value": [ { "text": "In this table and the ones that follow, I summarize what armed conflicts and conflict deaths each data source covers.", "spanType": "span-simple-text" }, { "url": "#note-7", "children": [ { "children": [ { "text": "7", "spanType": "span-simple-text" } ], "spanType": "span-superscript" } ], "spanType": "span-ref" } ], "parseErrors": [] }, { "type": "html", "value": "<table class=\"html-table\"><tr><td>UCDP</td><td><ul><li>Armed conflicts: interstate, intrastate, extrastate, non-state, and one-sided violence</li><li>At least 25 deaths during a year (based on most plausible estimate)<a class=\"ref\" href=\"#note-8\"><sup>8</sup></a></li></ul></td></tr><tr><td>Project Mars</td><td><ul><li>Conventional wars: interstate; de facto also intrastate and extrastate</li><li>At least 500 deaths (based on highest plausible estimate)</li><li>Primary combatants have differentiated militaries, and clear frontlines</li></ul></td></tr><tr><td>Militarized Interstate Events</td><td><ul><li>Militarized interstate confrontations: interstate threats of force, display of force, use of force, war</li></ul></td></tr><tr><td>Correlates of War \u2014 Wars</td><td><ul><li>Wars: interstate, intrastate, extrastate, and non-state</li><li>At least 1,000 deaths during a year</li></ul></td></tr><tr><td>Correlates of War \u2014 Militarized Interstate Disputes</td><td><ul><li>Militarized interstate disputes: interstate threats of force, display of force, use of force, war</li><li>At least use of force threatened</li><li>At least 1,000 deaths during a year for war</li></ul></td></tr><tr><td>Peace Research Institute Oslo</td><td><ul><li>Armed conflicts: interstate, intrastate, and extrastate</li><li>At least 25 deaths during a year</li></ul></td></tr><tr><td>Conflict Catalog</td><td><ul><li>Violent political conflicts: interstate, intrastate, extrastate, non-state and one-sided violence</li><li>At least 32 deaths during a year</li></ul></td></tr></table>", "parseErrors": [] }, { "type": "text", "value": [ { "text": "All sources characterize an armed conflict as a disagreement between organized groups that involves force. For most datasets, this means that force is used. But for the Militarized Interstate Events data and Correlates of War\u2019s Militarized Interstate Disputes data, this can also mean that force is threatened or displayed.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "Approaches also differ in what types of conflicts they cover and how many deaths they must cause to be included.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "They all include armed conflicts where the primary combatants are states (interstate conflicts), and most cover those conflicts between a state and an armed group that is not a state inside the state\u2019s territory (intrastate conflicts) or outside the state\u2019s territory (extrastate conflicts).", "spanType": "span-simple-text" }, { "url": "#note-9", "children": [ { "children": [ { "text": "9", "spanType": "span-simple-text" } ], "spanType": "span-superscript" } ], "spanType": "span-ref" }, { "text": " These conflicts are sometimes grouped together as \u201cstate-based\u201d conflicts.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "Some approaches go further and also include conflicts where neither armed group is a state (non-state conflicts). ", "spanType": "span-simple-text" }, { "url": "#note-10", "children": [ { "children": [ { "text": "10", "spanType": "span-simple-text" } ], "spanType": "span-superscript" } ], "spanType": "span-ref" }, { "text": " And some even include violence by an armed group \u2014 state or non-state \u2014 against civilians (one-sided violence).", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "Most sources only include conflicts if they cause many deaths. Some set a threshold of at least 500 or 1,000 annual or total deaths, and then call these deadly conflicts ", "spanType": "span-simple-text" }, { "children": [ { "text": "wars", "spanType": "span-simple-text" } ], "spanType": "span-italic" }, { "text": ". Others include more minor armed conflicts that cause a few dozen deaths during a year. And the Militarized Interstate Events data and Correlates of War\u2019s Militarized Interstate Disputes data also include conflicts in which no one died.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "Finally, the specific definitions of the sources mean that their conflicts differ slightly beyond their differences in conflict type and death toll. The biggest of these minor differences is that Project Mars only includes conventional wars, those fought between differentiated militaries along clear frontlines. Others do not make such a distinction.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "text": [ { "text": "Which deaths are included?", "spanType": "span-simple-text" } ], "type": "heading", "level": 1, "parseErrors": [] }, { "type": "text", "value": [ { "text": "The data sources also differ in who they include in their death counts and how they were killed.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "html", "value": "<table class=\"html-table\"><tr><td>UCDP</td><td><ul><li>Total, combatant, and civilian deaths, due to fighting</li></ul></td></tr><tr><td>Project Mars</td><td><ul><li>Deaths of combatants, due to fighting</li></ul></td></tr><tr><td>Militarized Interstate Events</td><td><ul><li>Deaths of combatants, due to fighting</li></ul></td></tr><tr><td>Correlates of War \u2014 War Data</td><td><ul><li>Deaths of combatants, due to fighting, disease, and starvation</li></ul></td></tr><tr><td>Correlates of War \u2014 Militarized Interstate Disputes</td><td><ul><li>Deaths of combatants, due to fighting</li></ul></td></tr><tr><td>Peace Research Institute Oslo</td><td><ul><li>Deaths of combatants and civilians, due to fighting</li></ul></td></tr><tr><td>Conflict Catalog</td><td><ul><li>Total, combatant, and civilian deaths, due to fighting, disease, and starvation</li></ul></td></tr></table>", "parseErrors": [] }, { "type": "text", "value": [ { "text": "All sources record deaths, the people killed in the conflict. This is different from other sources which record casualties, which include both deaths and those wounded. Yet other sources even tally losses, including both casualties and those deserted.", "spanType": "span-simple-text" }, { "url": "#note-11", "children": [ { "children": [ { "text": "11", "spanType": "span-simple-text" } ], "spanType": "span-superscript" } ], "spanType": "span-ref" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "But some approaches only include deaths of combatants \u2014 those doing the fighting. Others also include civilians \u2014 those who do not take up any weapons but may be killed accidentally or intentionally (in cases of one-sided violence).", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "These civilian deaths also include victims of terrorist attacks, as long as the attack was carried out by an armed group.", "spanType": "span-simple-text" }, { "url": "#note-12", "children": [ { "children": [ { "text": "12", "spanType": "span-simple-text" } ], "spanType": "span-superscript" } ], "spanType": "span-ref" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "And some approaches only include direct, or battle-related, deaths \u2014 those due to the fighting. Meanwhile, others include direct and indirect, or war-related, deaths \u2014 both those due to fighting, and those due to disease or starvation caused by the conflict.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "text": [ { "text": "What years and countries are covered?", "spanType": "span-simple-text" } ], "type": "heading", "level": 1, "parseErrors": [] }, { "type": "text", "value": [ { "text": "All data sources provide historical data and cover conflicts worldwide. But they differ in what years they cover, and which countries and regions they consider sovereign states.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "html", "value": "<table class=\"html-table\"><tr><td>UCDP</td><td><ul><li>1989 \u2014 ongoing</li><li>Global</li></ul></td></tr><tr><td>Project Mars</td><td><ul><li>1800 \u2014 2011 / ongoing</li><li>Global</li></ul></td></tr><tr><td>Militarized Interstate Events</td><td><ul><li>1816 \u2014 2014 / ongoing</li><li>Global</li></ul></td></tr><tr><td>Correlates of War \u2014 War Data</td><td><ul><li>1816 \u2014 2007 (extrastate, non-state), 1816 \u2014 2010 (inter-state), 1816 \u2014 2014 (intrastate) / ongoing</li><li>Global</li></ul></td></tr><tr><td>Correlates of War \u2014 Militarized Interstate Disputes</td><td><ul><li>1816 \u2014 2014 / ongoing</li><li>Global</li></ul></td></tr><tr><td>Peace Research Institute Oslo</td><td><ul><li>1946 \u2014 2008</li><li>Global</li></ul></td></tr><tr><td>Conflict Catalog</td><td><ul><li>1400 \u2014 2000</li><li>Global</li></ul></td></tr></table>", "parseErrors": [] }, { "type": "text", "value": [ { "text": "UCDP currently provides the most recent data, as it is updated each year. Other sources are updated less frequently and currently have a delay of about a decade on their most recent data (Project Mars, Militarized Interstate Events, and Correlates of War), or they are no longer maintained and will likely not be updated for recent decades (Conflict Catalog and PRIO).", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "In turn, UCDP only begins at the end of the Cold War. In contrast, the other sources start in the mid- or early 20th century (PRIO), the early 19th century (Project Mars, Militarized Interstate Events, and Correlates of War), or even reach as far back in time as the year 1400 (Conflict Catalog).", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "The data sources also differ in which countries and regions they consider sovereign states. Correlates of War and Militarized Interstate Events use the state system by ", "spanType": "span-simple-text" }, { "url": "https://ourworldindata.org/grapher/sovereign-state-cow", "children": [ { "text": "Correlates of War", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": ", which until 1919 requires diplomatic recognition by France and the United Kingdom for a country to be included.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "UCDP and PRIO meanwhile use the slightly more inclusive list of sovereign states by ", "spanType": "span-simple-text" }, { "url": "https://ourworldindata.org/grapher/sovereign-state-gleditsch-ward", "children": [ { "text": "Gleditsch and Ward", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": ". Project Mars and the Conflict Catalog have even more expansive definitions of statehood, and are closer to the state system as identified by ", "spanType": "span-simple-text" }, { "url": "https://ourworldindata.org/grapher/sovereign-state-butcher-griffiths", "children": [ { "text": "Butcher and Griffiths", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": ".", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "This affects how some conflicts are classified, as an extrastate or non-state war in Correlates of War\u2019s war data can be classified as an interstate or civil war in Project Mars. And it affects how conflict rates are ", "spanType": "span-simple-text" }, { "url": "https://docs.google.com/document/d/1H_dmh_1YYoY605lcVHtyOm2RZ2AfpIUuimG99ubmcHs/edit", "children": [ { "text": "calculated", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": ", as the number of countries for each year can ", "spanType": "span-simple-text" }, { "url": "https://ourworldindata.org/grapher/number-of-countries", "children": [ { "text": "differ a lot", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": ", ", "spanType": "span-simple-text" }, { "url": "https://ourworldindata.org/grapher/number-of-countries-by-region", "children": [ { "text": "especially", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": " for Africa and Asia and Oceania.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "text": [ { "text": "How are conflicts and deaths identified?", "spanType": "span-simple-text" } ], "type": "heading", "level": 1, "parseErrors": [] }, { "type": "text", "value": [ { "text": "Generally, the data sources are similar in how they go about assessing conflicts and the deaths in them.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "html", "value": "<table class=\"html-table\"><tr><td>UCDP</td><td><ul><li>Evaluations by own researchers of news reports, other contemporary sources, and academic research</li></ul></td></tr><tr><td>Project Mars</td><td><ul><li>Evaluations by own researchers of academic research (including UCDP and CoW), news reports, and other contemporary sources</li></ul></td></tr><tr><td>Militarized Interstate Events</td><td><ul><li>Evaluations by own researchers of academic research (including CoW) and news reports, other contemporary sources, and academic research</li></ul></td></tr><tr><td>Correlates of War \u2014 War Data</td><td><ul><li>Evaluations by own researchers of academic research</li></ul></td></tr><tr><td>Correlates of War \u2014 Militarized Interstate Disputes</td><td><ul><li>Evaluations by own researchers of academic research and news reports filtered by machine learning</li></ul></td></tr><tr><td>Peace Research Institute Oslo</td><td><ul><li>Evaluations by own researchers of academic research (including UCDP), official death statistics, surveys, news reports, and other archival sources<a class=\"ref\" href=\"#note-13\"><sup>13</sup></a></li></ul></td></tr><tr><td>Conflict Catalog</td><td><ul><li>Own evaluations of academic research (including CoW) and other sources</li></ul></td></tr></table>", "parseErrors": [] }, { "type": "text", "value": [ { "text": "All rely on researchers evaluating independent news reports, academic research, or both. Some also supplement these primary sources with available surveys of the affected populations, or official death statistics.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "The primary sources they use can partially overlap. Some use the same sources, such as the encyclopedias by Micheal Clodfelter", "spanType": "span-simple-text" }, { "url": "#note-14", "children": [ { "children": [ { "text": "14", "spanType": "span-simple-text" } ], "spanType": "span-superscript" } ], "spanType": "span-ref" }, { "text": " Lewis Fry Richardson", "spanType": "span-simple-text" }, { "url": "#note-15", "children": [ { "children": [ { "text": "15", "spanType": "span-simple-text" } ], "spanType": "span-superscript" } ], "spanType": "span-ref" }, { "text": ", and Pitirim Sorokin", "spanType": "span-simple-text" }, { "url": "#note-16", "children": [ { "children": [ { "text": "16", "spanType": "span-simple-text" } ], "spanType": "span-superscript" } ], "spanType": "span-ref" }, { "text": ". Or they outright rely on each other as the sources: PRIO and Project Mars use UCDP data, and Project Mars, Militarized Interstate Events, and the Conflict Catalog build on Correlates of War.", "spanType": "span-simple-text" }, { "url": "#note-17", "children": [ { "children": [ { "text": "17", "spanType": "span-simple-text" } ], "spanType": "span-superscript" } ], "spanType": "span-ref" } ], "parseErrors": [] }, { "text": [ { "text": "How do sources work to measure what they want to measure?", "spanType": "span-simple-text" } ], "type": "heading", "level": 1, "parseErrors": [] }, { "type": "text", "value": [ { "text": "The next tables summarize how the data sources address the specific challenges of measuring armed conflicts and conflict deaths. The first challenge is to make their assessments valid \u2014 to actually measure what they want to measure.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "html", "value": "<table class=\"html-table\"><tr><td>UCDP</td><td><ul><li>Own researchers know measurement procedures and conflicts well</li><li>Include civilian deaths, as difference to combatants can be blurry</li><li>Exclude deaths due to disease and starvation as well as wounded, as difficult to identify</li></ul></td></tr><tr><td>Project Mars</td><td><ul><li>Own researchers know measurement procedures well</li><li>Exclude civilian deaths, deaths due to disease and starvation, as well as wounded, as interested in military lethality on the battlefield</li></ul></td></tr><tr><td>Militarized Interstate Events</td><td><ul><li>Own researchers know measurement procedures well</li><li>Investigate closely country-pairs with high predicted likelihood of conflict</li></ul></td></tr><tr><td>Correlates of War \u2014 War Data</td><td><ul><li>Own researchers know measurement procedures well</li><li>Include deaths due to disease and starvation, as they are integral to war, and often not distinguished from fighting in sources</li><li>Exclude civilian deaths, as difficult to identify</li><li>Sometimes estimate deaths if only number of casualties available</li></ul></td></tr><tr><td>Correlates of War \u2014 Militarized Interstate Disputes</td><td><ul><li>Own researchers know measurement procedures well</li><li>Machine learning can process vast numbers of news reports</li><li>Group deaths into broad ranges because number of deaths often uncertain</li></ul></td></tr><tr><td>Peace Research Institute Oslo</td><td><ul><li>Own researchers know measurement procedures well</li><li>Include civilian deaths, as difference to combatants can be blurry</li><li>Exclude deaths due to disease and starvation, as difficult to identify</li></ul></td></tr><tr><td>Conflict Catalog</td><td><ul><li>Own researchers know measurement procedures well</li></ul></td></tr></table>", "parseErrors": [] }, { "type": "text", "value": [ { "text": "In general, the sources relying on their own researchers have the advantage that these researchers know the respective definitions of armed conflicts and related deaths well and are very familiar with the measurement procedures, which makes it more likely that they code as intended.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "However, the sources differ in the deaths they include because they weigh the challenges of measurement differently. Some include civilian deaths because they often find it too difficult to distinguish them from combatant deaths.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "Others exclude them because they find them too difficult to identify comprehensively or because they are only interested in the actions of militaries on the battlefield.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "Some approaches include deaths due to disease and starvation because they consider them a fundamental part of war, and because primary sources often do not distinguish between them and deaths due to fighting. But others do not, as they find such indirect deaths too challenging to identify comprehensively.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "Finally, Correlates of War\u2019s war data sometimes estimates the number of deaths based on the number of conflict casualties, if only those are available. And its Militarized Interstate Disputes data mostly groups deaths into broad ranges, as it finds determining more specific numbers too uncertain.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "text": [ { "text": "How do sources work to make assessments precise?", "spanType": "span-simple-text" } ], "type": "heading", "level": 1, "parseErrors": [] }, { "type": "text", "value": [ { "text": "The sources are also concerned with making their assessments precise and reliable.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "html", "value": "<table class=\"html-table\"><tr><td>UCDP</td><td><ul><li>Many and different types of sources used</li><li>Not covering earlier years</li><li>Conflicts disaggregated into years and individual events (with at least one death per event)</li><li>Report types of deaths separately</li></ul></td></tr><tr><td>Project Mars</td><td><ul><li>More than 100 researchers split into adversarial teams search at least 10 quality sources per deaths estimate</li><li>Not covering earlier years</li><li>Big and recurrent wars disaggregated into campaigns</li></ul></td></tr><tr><td>Militarized Interstate Events</td><td><ul><li>Many and different types of primary sources used</li><li>Not covering earlier years</li><li>Conflicts disaggregated into years and individual events</li></ul></td></tr><tr><td>Correlates of War \u2014 War Data</td><td><ul><li>Many and different types of primary sources used</li><li>Not covering earlier years</li></ul></td></tr><tr><td>Correlates of War \u2014 Militarized Interstate Disputes</td><td><ul><li>Many and different types of primary sources used</li><li>Not covering earlier years</li><li>Conflicts partially disaggregated into individual incidents</li></ul></td></tr><tr><td>Peace Research Institute Oslo</td><td><ul><li>Many and different types of sources used</li><li>Not covering earlier years</li><li>Conflicts disaggregated into years</li></ul></td></tr><tr><td>Conflict Catalog</td><td><ul><li>Many and different types of primary sources used</li><li>Not covering earlier years</li><li>Big conflicts disaggregated into smaller ones</li><li>Report types of deaths separately</li></ul></td></tr></table>", "parseErrors": [] }, { "type": "text", "value": [ { "text": "They all use many primary sources, and most use different types of sources, such as news reports, academic books and articles, or NGO documents.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "They also all avoid covering conflicts that happened even earlier \u2014 even though they differ in how far they think they can go back in time and still have data that is sufficiently reliable: UCDP begins in 1989, whereas the Conflict Catalog starts in the year 1400.", "spanType": "span-simple-text" }, { "url": "#note-18", "children": [ { "children": [ { "text": "18", "spanType": "span-simple-text" } ], "spanType": "span-superscript" } ], "spanType": "span-ref" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "Several sources also disaggregate their data to make it more precise: they split their estimates of deaths into total, combatant, and civilian deaths, when possible; disaggregate bigger conflicts into smaller ones; or each conflict into years, campaigns, or even specific events.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "text": [ { "text": "How do sources work to make assessments comparable?", "spanType": "span-simple-text" } ], "type": "heading", "level": 1, "parseErrors": [] }, { "type": "text", "value": [ { "text": "The sources also face the challenge of making the data comparable across conflicts and time.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "html", "value": "<table class=\"html-table\"><tr><td>UCDP</td><td><ul><li>Researchers have very precise definitions of conflict, deaths, and other event characteristics</li><li>Global news used first, then (sometimes translated) local and specialized sources</li></ul></td></tr><tr><td>Project Mars</td><td><ul><li>Researchers have very precise definitions of conflict and deaths</li><li>Primary sources in 21 languages used</li></ul></td></tr><tr><td>Militarized Interstate Events</td><td><ul><li>Exclude civilian deaths, as they have become more common</li><li>Global news used because more comprehensive</li></ul></td></tr><tr><td>Correlates of War \u2014 War Data</td><td><ul><li>Exclude civilian deaths, as they have become more common</li></ul></td></tr><tr><td>Correlates of War \u2014 Militarized Interstate Disputes</td><td><ul><li>Exclude civilian deaths, as they have become more common</li><li>Global news used because more comprehensive</li></ul></td></tr><tr><td>Peace Research Institute Oslo</td><td><ul><li>Researchers have precise definitions of conflict and deaths</li></ul></td></tr><tr><td>Conflict Catalog</td><td><ul><li>Also non-English sources used</li></ul></td></tr></table>", "parseErrors": [] }, { "type": "text", "value": [ { "text": "Some do so by providing their researchers with precise definitions of conflicts and deaths, making it easier to decide which to include.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "And some also use primary sources in different languages or first identify conflicts and deaths with global sources and then use more local ones. Others, meanwhile, prefer global sources for their more comprehensive coverage of international affairs.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "text": [ { "text": "How are the remaining differences between primary sources dealt with?", "spanType": "span-simple-text" } ], "type": "heading", "level": 1, "parseErrors": [] }, { "type": "text", "value": [ { "text": "The sources work to address any remaining differences between primary sources, even if they do so differently.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "html", "value": "<table class=\"html-table\"><tr><td>UCDP</td><td><ul><li>Consider quality of primary sources, discuss within team, use most reliable one</li><li>Provide best, low, and high deaths estimates provided if several plausible</li><li>Use lower as the best estimate if no primary source is more reliable than others; best estimate therefore likely no overcount</li></ul></td></tr><tr><td>Project Mars</td><td><ul><li>Consider quality of primary sources, discuss among coder teams</li><li>Provide low and high estimates</li></ul></td></tr><tr><td>Militarized Interstate Events</td><td><ul><li>Consider quality of primary sources, discuss among coders</li><li>Provide low and high estimates</li></ul></td></tr><tr><td>Correlates of War \u2014 War Data</td><td><ul><li>Consider quality of primary sources and context (army size, weapons, medical technology, etc.)</li></ul></td></tr><tr><td>Correlates of War \u2014 Militarized Interstate Disputes</td><td><ul><li>Consider quality of primary sources, discuss among coders</li><li>Provide low and high estimates</li><li>Include accusations by targeted state even if denied by allegedly targeting state</li></ul></td></tr><tr><td>Peace Research Institute Oslo</td><td><ul><li>Consider quality of primary sources, use most reliable one</li><li>Provide best, low, and high deaths estimates</li></ul></td></tr><tr><td>Conflict Catalog</td><td><ul><li>Consider quality of primary sources</li></ul></td></tr></table>", "parseErrors": [] }, { "type": "text", "value": [ { "text": "They all consider the quality of primary sources and prefer more reliable ones. Some also consider the context of the conflicts \u2014 such as army size and weapons used \u2014 to assess which accounts are more plausible.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "Others also discuss any discrepancies between researchers on their team. This adds an additional step to make the assessments comparable across coders, conflicts, and time.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "Correlates of War\u2019s Militarized Interstate Disputes data partially reconciles differences between conflict parties by erring on the side of including accusations by a targeted state even if the state allegedly targeting it denies them.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "Several approaches provide more than one estimate of conflict deaths and share a low, high, and sometimes also a best estimate. By doing so, they avoid forcing themselves to eliminate all uncertainty and possibly biasing their estimates.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "UCDP combines these strategies and uses the lower estimate as the best one if no primary source is more reliable than others. It thereby reduces the risk that the estimate overcounts deaths.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "text": [ { "text": "How do sources work to make data accessible and transparent?", "spanType": "span-simple-text" } ], "type": "heading", "level": 1, "parseErrors": [] }, { "type": "text", "value": [ { "text": "Finally, the data sources all make their data accessible and the underlying measurement transparent. They all publicly release their data, and most make it straightforward to download and use.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "html", "value": "<table class=\"html-table\"><tr><td>UCDP</td><td><ul><li>Very detailed coding procedures are available and easy to access</li><li>Justifies conflict and death characteristics</li><li>Provides primary source(s) for each event</li><li>Provides context with conflict narratives</li></ul></td></tr><tr><td>Project Mars</td><td><ul><li>Very detailed coding procedures are available and easy to access</li><li>Justifies conflict and death characteristics</li></ul></td></tr><tr><td>Militarized Interstate Events</td><td><ul><li>Detailed coding procedures are available and easy to access</li><li>Justifies conflict and deaths characteristics</li><li>Provides context with conflict narratives</li></ul></td></tr><tr><td>Correlates of War \u2014 War Data</td><td><ul><li>Coding procedures are available and partially easy to access</li><li>Justifies conflict and death characteristics</li><li>Provides context with conflict narratives</li></ul></td></tr><tr><td>Correlates of War \u2014 Militarized Interstate Disputes</td><td><ul><li>Very detailed coding procedures are available and partially easy to access</li><li>Justifies conflict and deaths characteristics</li><li>Partially provides context with conflict narratives</li></ul></td></tr><tr><td>Peace Research Institute Oslo</td><td><ul><li>Detailed coding procedures are available and easy to access</li><li>Justifies conflict and death characteristics</li></ul></td></tr><tr><td>Conflict Catalog</td><td><ul><li>Coding procedures are available and easy to access</li></ul></td></tr></table>", "parseErrors": [] }, { "type": "text", "value": [ { "text": "All release descriptions of how they characterize conflicts and deaths and share at least some of the coding procedures guiding the researchers.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "Militarized Interstate Events and Correlates of War also provide additional helpful information by describing conflicts in accompanying reports. And UCDP shares the primary sources for each event underlying every conflict.", "spanType": "span-simple-text" }, { "url": "#note-19", "children": [ { "children": [ { "text": "19", "spanType": "span-simple-text" } ], "spanType": "span-superscript" } ], "spanType": "span-ref" } ], "parseErrors": [] }, { "text": [ { "text": "The best source depends on your questions", "spanType": "span-simple-text" } ], "type": "heading", "level": 1, "parseErrors": [] }, { "type": "text", "value": [ { "text": "There is no single \u2018best\u2019 approach to measuring armed conflicts and their deaths. All sources put a lot of effort into measuring conflicts and deaths in ways that are useful to researchers, policymakers, and interested citizens.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "The most appropriate source depends on what questions you want to answer. It is the one that captures the conflicts, deaths, and time you are interested in.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "If you are interested in both big and smaller conflicts in recent years, in combatant and civilian deaths, or also non-state conflicts and acts of one-sided violence, UCDP is best.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "If you are less interested in the most recent years and more in big and smaller conflicts that involve at least one state in the decades since World War II, PRIO data is best. If you also want the most recent years, you can use our combined UCDP+PRIO data.", "spanType": "span-simple-text" }, { "url": "#note-20", "children": [ { "children": [ { "text": "20", "spanType": "span-simple-text" } ], "spanType": "span-superscript" } ], "spanType": "span-ref" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "If you want to study long-term differences and changes over the last two hundred years and it is sufficient to focus on bigger conflicts, then Project Mars is best.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "If you are especially interested in specific types of large conflicts over recent centuries, the Correlates of War data is best.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "If, instead, you want to explore both big and small conflicts between ", "spanType": "span-simple-text" }, { "children": [ { "text": "states", "spanType": "span-simple-text" } ], "spanType": "span-italic" }, { "text": ", the Militarized Interstate Events data is best.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "If you want to explore the source that was researchers\u2019 go-to for interstate conflicts for a long time and are fine with its less precise data, Correlates of War\u2019s Militarized Interstate Disputes data is best.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "And if you want to study bigger conflicts over more than the last half millennium and are willing to accept lower data quality, the Conflict Catalog is best.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "Even if you have a preferred source, it can still be useful to see what other sources show and where they agree and differ.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "This means that having several approaches to measuring conflict deaths is not a flaw but a strength: it gives us different tools to understand the past, current state, and possible future of armed conflict around the world.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "If you want to explore and compare the data that each dataset produces, you can do so in our work on ", "spanType": "span-simple-text" }, { "url": "https://docs.google.com/document/d/1fdECw4wt6d7_-cIeMcsBfnoUEoeKwF2Z1gj3Y8RCF4g/edit", "children": [ { "text": "War and Peace", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": " and in our ", "spanType": "span-simple-text" }, { "url": "https://docs.google.com/document/d/1SpyofFwtTSpD69fW6rUq-D-zM6DSsW7I7l0_bNC-AMA/edit", "children": [ { "text": "Conflict Data Explorers", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": ".", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "text": [ { "type": "text", "value": [ { "text": "I thank Edouard Mathieu, Hannah Ritchie, and Max Roser for reading drafts of this text and for very helpful comments and ideas.", "spanType": "span-simple-text" } ], "parseErrors": [] } ], "type": "callout", "title": "Acknowledgements", "parseErrors": [] }, { "text": [ { "text": "Keep reading at Our World in Data", "spanType": "span-simple-text" } ], "type": "heading", "level": 2, "parseErrors": [] }, { "url": "https://docs.google.com/document/d/1H_dmh_1YYoY605lcVHtyOm2RZ2AfpIUuimG99ubmcHs/edit", "type": "prominent-link", "parseErrors": [] }, { "url": "https://docs.google.com/document/d/1SpyofFwtTSpD69fW6rUq-D-zM6DSsW7I7l0_bNC-AMA/edit", "type": "prominent-link", "parseErrors": [] } ], "refs": { "errors": [], "definitions": { "correlates_of_war": { "id": "correlates_of_war", "index": 3, "content": [ { "type": "text", "value": [ { "text": "Sarkees, Meredith Reid, and Frank Wayman. 2010. ", "spanType": "span-simple-text" }, { "url": "https://archive.org/details/resorttowardatag0000sark/page/450/mode/2up", "children": [ { "text": "Resort to War: A Data Guide to Inter-State, Extra-State, Intra-State, and Non-State Wars, 1816-2007", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": ". CQ Press.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "Palmer, Glenn, Roseanne McManus, Vito D\u2019Orazio, Michael Kenwick, Mikaela Karstens, Chase Bloch, Nick Dietrich, Kayla Kahn, Kellan Ritter, and Michael Soules. 2021. ", "spanType": "span-simple-text" }, { "url": "https://journals.sagepub.com/doi/full/10.1177/0738894221995743", "children": [ { "text": "The MID5 Dataset, 2011-2014: Procedures, coding rules, and description", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": ". Conflict Management and Peace Science 38(5): 470-482.", "spanType": "span-simple-text" } ], "parseErrors": [] } ], "parseErrors": [] }, "ucdp_prio_differences": { "id": "ucdp_prio_differences", "index": 12, "content": [ { "type": "text", "value": [ { "text": "While UCDP and PRIO cover the same deaths and partially the same conflicts, their different sources often lead to somewhat different estimates:", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "UCDP collects data on deaths for each individual conflict event, whereas PRIO uses less specific summary estimates.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "UCDP also looks at non-state conflicts and one-sided violence, which PRIO does not. Yet, PRIO\u2019s summary estimates may still partially include deaths from non-state conflicts or one-sided violence that are closely tied to the state-based conflicts it covers.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "UCDP only includes an event if it can identify the perpetrator. Because PRIO does not look at events, its summary estimates may partially include deaths where a likely perpetrator was identified as likely, but not conclusively determined.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "These differences explain why UCDP tends to report fewer deaths than PRIO.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "The joint UCDP and PRIO report ", "spanType": "span-simple-text" }, { "url": "https://www.pcr.uu.se/digitalAssets/666/c_666984-l_1-k_hsrp_est.battle_deaths_1.2.13.pdf", "children": [ { "text": "Estimating Battle Deaths: A Challenging Exercise", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": " discusses this further.", "spanType": "span-simple-text" } ], "parseErrors": [] } ], "parseErrors": [] }, "militarized_interstate_events": { "id": "militarized_interstate_events", "index": 2, "content": [ { "type": "text", "value": [ { "text": "Gibler, Douglas, and Steven Miller. 2023. ", "spanType": "span-simple-text" }, { "url": "https://journals.sagepub.com/doi/abs/10.1177/00220027221104704", "children": [ { "text": "The Militarized Interstate Confrontation Dataset, 1816-2014", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": ". Journal of Conflict Resolution. OnlineFirst.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "Gibler, Douglas, and Steven Miller. 2023. ", "spanType": "span-simple-text" }, { "url": "https://journals.sagepub.com/doi/abs/10.1177/07388942231182674", "children": [ { "text": "The Militarized Interstate Events (MIE) dataset, 1816\u20132014", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": ". Conflict Management and Peace Science. OnlineFirst.", "spanType": "span-simple-text" } ], "parseErrors": [] } ], "parseErrors": [] }, "uppsala_conflict_data_program": { "id": "uppsala_conflict_data_program", "index": 0, "content": [ { "type": "text", "value": [ { "text": "Davies, Shawn, Therese Pettersson, and Magnus \u00d6berg. 2023. Organized violence 1989-2022 and the return of conflicts between states? Journal of Peace Research 60(4): 691-708.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "Gleditsch, Nils Petter, Peter Wallensteen, Mikael Eriksson, Margareta Sollenberg, and H\u00e5vard Strand. 2002. ", "spanType": "span-simple-text" }, { "url": "https://journals.sagepub.com/doi/10.1177/0022343302039005007", "children": [ { "text": "Armed conflict 1946\u20132001: A new dataset", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": ". 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Paper prepared for the 1999 Meeting of the Peace Science Society (International) on October 8-10, 1999 in Ann Arbor, Michigan.", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "Brecke, Peter. 2012. ", "spanType": "span-simple-text" }, { "url": "http://www.cgeh.nl/sites/default/files/Notes%20about%20Conflict%20Catalog.pdf", "children": [ { "text": "Notes regarding the Conflict Catalog", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": ".", "spanType": "span-simple-text" } ], "parseErrors": [] }, { "type": "text", "value": [ { "text": "Eck, Kristine, and Lisa Hultman. 2007. ", "spanType": "span-simple-text" }, { "url": "https://journals.sagepub.com/doi/10.1177/0022343307075124", "children": [ { "text": "One-sided violence against civilians in war: insights from new fatality data", "spanType": "span-simple-text" } ], "spanType": "span-link" }, { "text": ". 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Journal of Peace Research 49(2): 351-362.", "spanType": "span-simple-text" } ], "parseErrors": [] } ], "parseErrors": [] }, "ee38be823e56bcf657cb3eaf7a1987ce7ecfc680": { "id": "ee38be823e56bcf657cb3eaf7a1987ce7ecfc680", "index": 18, "content": [ { "type": "text", "value": [ { "text": "Militarized Interstate Events has plans to share the source(s) for each of its events.", "spanType": "span-simple-text" } ], "parseErrors": [] } ], "parseErrors": [] } } }, "type": "article", "title": "How major sources collect data on conflicts and conflict deaths, and when to use which one", "authors": [ "Bastian Herre" ], "excerpt": "There are many ways to measure armed conflicts and conflict deaths. What approaches do different researchers take? And when is which approach best?", "subtitle": "There are many ways to measure armed conflicts and conflict deaths. What approaches do different researchers take? And when is which approach best?", "featured-image": "conflict-data-how-do-researchers-measure-armed-conflicts-and-their-deaths.png" }	1	2023-06-29 15:51:04	2023-10-13 16:03:57	2024-02-16 17:38:25	listed	ALBJ4LtK-EByjfcUxy39xDrpmN9MbzvWUx0FWttqpQ3NyRonMvtcxWRuCvmj16NYMMtMMpiMCJVSmOUICbVRyg		<Callout title="More on conflict data"/> Measuring armed conflicts and conflict deaths across the world helps us understand how people’s lives and livelihoods are affected by large-scale violence. But this comes with many challenges. People do not always agree on what characteristics define an armed conflict. Even once defined, these characteristics — especially how many people died in them — are difficult to assess. The people affected are not always asked who has died around them due to the conflict. The conflict parties may underreport deaths to claim success, or overreport them to encourage intervention by third parties. Independent observers may also struggle to be present in all places and document a conflict’s death toll. So how do researchers address these challenges? In our work on [War and Peace](https://ourworldindata.org/war-and-peace), we provide data from six sources that identify armed conflicts and count their deaths: * Uppsala Conflict Data Program (UCDP)1 * Project Mars by Jason Lyall (2022)2 * Militarized Interstate Events by Douglas Gibler and Steven Miller3 * Correlates of War (CoW)4 * Peace Research Institute Oslo (PRIO)5 * Conflict Catalog by Peter Brecke (1999)6 These sources all measure armed conflicts and their deaths; they cover many countries and years, and researchers and policymakers frequently use them. In our [Conflict Data Explorers](https://docs.google.com/document/d/1SpyofFwtTSpD69fW6rUq-D-zM6DSsW7I7l0_bNC-AMA/edit), you can delve into global and regional overviews of conflicts and their deaths. Reassuringly, sources typically agree about big differences in the deaths from armed conflicts: they readily distinguish between deadly and peaceful years. But they do not always agree. They often come to different assessments about _how _widespread and deadly some years were. Why do these sources arrive at different numbers? And is there any best approach? I summarize the key similarities and differences between the different approaches in this article and when to use which one. # What conflicts are covered? In this table and the ones that follow, I summarize what armed conflicts and conflict deaths each data source covers.7 <table class="html-table"><tr><td>UCDP</td><td><ul><li>Armed conflicts: interstate, intrastate, extrastate, non-state, and one-sided violence</li><li>At least 25 deaths during a year (based on most plausible estimate)<a class="ref" href="#note-8"><sup>8</sup></a></li></ul></td></tr><tr><td>Project Mars</td><td><ul><li>Conventional wars: interstate; de facto also intrastate and extrastate</li><li>At least 500 deaths (based on highest plausible estimate)</li><li>Primary combatants have differentiated militaries, and clear frontlines</li></ul></td></tr><tr><td>Militarized Interstate Events</td><td><ul><li>Militarized interstate confrontations: interstate threats of force, display of force, use of force, war</li></ul></td></tr><tr><td>Correlates of War — Wars</td><td><ul><li>Wars: interstate, intrastate, extrastate, and non-state</li><li>At least 1,000 deaths during a year</li></ul></td></tr><tr><td>Correlates of War — Militarized Interstate Disputes</td><td><ul><li>Militarized interstate disputes: interstate threats of force, display of force, use of force, war</li><li>At least use of force threatened</li><li>At least 1,000 deaths during a year for war</li></ul></td></tr><tr><td>Peace Research Institute Oslo</td><td><ul><li>Armed conflicts: interstate, intrastate, and extrastate</li><li>At least 25 deaths during a year</li></ul></td></tr><tr><td>Conflict Catalog</td><td><ul><li>Violent political conflicts: interstate, intrastate, extrastate, non-state and one-sided violence</li><li>At least 32 deaths during a year</li></ul></td></tr></table> All sources characterize an armed conflict as a disagreement between organized groups that involves force. For most datasets, this means that force is used. But for the Militarized Interstate Events data and Correlates of War’s Militarized Interstate Disputes data, this can also mean that force is threatened or displayed. Approaches also differ in what types of conflicts they cover and how many deaths they must cause to be included. They all include armed conflicts where the primary combatants are states (interstate conflicts), and most cover those conflicts between a state and an armed group that is not a state inside the state’s territory (intrastate conflicts) or outside the state’s territory (extrastate conflicts).9 These conflicts are sometimes grouped together as “state-based” conflicts. Some approaches go further and also include conflicts where neither armed group is a state (non-state conflicts). 10 And some even include violence by an armed group — state or non-state — against civilians (one-sided violence). Most sources only include conflicts if they cause many deaths. Some set a threshold of at least 500 or 1,000 annual or total deaths, and then call these deadly conflicts _wars_. Others include more minor armed conflicts that cause a few dozen deaths during a year. And the Militarized Interstate Events data and Correlates of War’s Militarized Interstate Disputes data also include conflicts in which no one died. Finally, the specific definitions of the sources mean that their conflicts differ slightly beyond their differences in conflict type and death toll. The biggest of these minor differences is that Project Mars only includes conventional wars, those fought between differentiated militaries along clear frontlines. Others do not make such a distinction. # Which deaths are included? The data sources also differ in who they include in their death counts and how they were killed. <table class="html-table"><tr><td>UCDP</td><td><ul><li>Total, combatant, and civilian deaths, due to fighting</li></ul></td></tr><tr><td>Project Mars</td><td><ul><li>Deaths of combatants, due to fighting</li></ul></td></tr><tr><td>Militarized Interstate Events</td><td><ul><li>Deaths of combatants, due to fighting</li></ul></td></tr><tr><td>Correlates of War — War Data</td><td><ul><li>Deaths of combatants, due to fighting, disease, and starvation</li></ul></td></tr><tr><td>Correlates of War — Militarized Interstate Disputes</td><td><ul><li>Deaths of combatants, due to fighting</li></ul></td></tr><tr><td>Peace Research Institute Oslo</td><td><ul><li>Deaths of combatants and civilians, due to fighting</li></ul></td></tr><tr><td>Conflict Catalog</td><td><ul><li>Total, combatant, and civilian deaths, due to fighting, disease, and starvation</li></ul></td></tr></table> All sources record deaths, the people killed in the conflict. This is different from other sources which record casualties, which include both deaths and those wounded. Yet other sources even tally losses, including both casualties and those deserted.11 But some approaches only include deaths of combatants — those doing the fighting. Others also include civilians — those who do not take up any weapons but may be killed accidentally or intentionally (in cases of one-sided violence). These civilian deaths also include victims of terrorist attacks, as long as the attack was carried out by an armed group.12 And some approaches only include direct, or battle-related, deaths — those due to the fighting. Meanwhile, others include direct and indirect, or war-related, deaths — both those due to fighting, and those due to disease or starvation caused by the conflict. # What years and countries are covered? All data sources provide historical data and cover conflicts worldwide. But they differ in what years they cover, and which countries and regions they consider sovereign states. <table class="html-table"><tr><td>UCDP</td><td><ul><li>1989 — ongoing</li><li>Global</li></ul></td></tr><tr><td>Project Mars</td><td><ul><li>1800 — 2011 / ongoing</li><li>Global</li></ul></td></tr><tr><td>Militarized Interstate Events</td><td><ul><li>1816 — 2014 / ongoing</li><li>Global</li></ul></td></tr><tr><td>Correlates of War — War Data</td><td><ul><li>1816 — 2007 (extrastate, non-state), 1816 — 2010 (inter-state), 1816 — 2014 (intrastate) / ongoing</li><li>Global</li></ul></td></tr><tr><td>Correlates of War — Militarized Interstate Disputes</td><td><ul><li>1816 — 2014 / ongoing</li><li>Global</li></ul></td></tr><tr><td>Peace Research Institute Oslo</td><td><ul><li>1946 — 2008</li><li>Global</li></ul></td></tr><tr><td>Conflict Catalog</td><td><ul><li>1400 — 2000</li><li>Global</li></ul></td></tr></table> UCDP currently provides the most recent data, as it is updated each year. Other sources are updated less frequently and currently have a delay of about a decade on their most recent data (Project Mars, Militarized Interstate Events, and Correlates of War), or they are no longer maintained and will likely not be updated for recent decades (Conflict Catalog and PRIO). In turn, UCDP only begins at the end of the Cold War. In contrast, the other sources start in the mid- or early 20th century (PRIO), the early 19th century (Project Mars, Militarized Interstate Events, and Correlates of War), or even reach as far back in time as the year 1400 (Conflict Catalog). The data sources also differ in which countries and regions they consider sovereign states. Correlates of War and Militarized Interstate Events use the state system by [Correlates of War](https://ourworldindata.org/grapher/sovereign-state-cow), which until 1919 requires diplomatic recognition by France and the United Kingdom for a country to be included. UCDP and PRIO meanwhile use the slightly more inclusive list of sovereign states by [Gleditsch and Ward](https://ourworldindata.org/grapher/sovereign-state-gleditsch-ward). Project Mars and the Conflict Catalog have even more expansive definitions of statehood, and are closer to the state system as identified by [Butcher and Griffiths](https://ourworldindata.org/grapher/sovereign-state-butcher-griffiths). This affects how some conflicts are classified, as an extrastate or non-state war in Correlates of War’s war data can be classified as an interstate or civil war in Project Mars. And it affects how conflict rates are [calculated](https://docs.google.com/document/d/1H_dmh_1YYoY605lcVHtyOm2RZ2AfpIUuimG99ubmcHs/edit), as the number of countries for each year can [differ a lot](https://ourworldindata.org/grapher/number-of-countries), [especially](https://ourworldindata.org/grapher/number-of-countries-by-region) for Africa and Asia and Oceania. # How are conflicts and deaths identified? Generally, the data sources are similar in how they go about assessing conflicts and the deaths in them. <table class="html-table"><tr><td>UCDP</td><td><ul><li>Evaluations by own researchers of news reports, other contemporary sources, and academic research</li></ul></td></tr><tr><td>Project Mars</td><td><ul><li>Evaluations by own researchers of academic research (including UCDP and CoW), news reports, and other contemporary sources</li></ul></td></tr><tr><td>Militarized Interstate Events</td><td><ul><li>Evaluations by own researchers of academic research (including CoW) and news reports, other contemporary sources, and academic research</li></ul></td></tr><tr><td>Correlates of War — War Data</td><td><ul><li>Evaluations by own researchers of academic research</li></ul></td></tr><tr><td>Correlates of War — Militarized Interstate Disputes</td><td><ul><li>Evaluations by own researchers of academic research and news reports filtered by machine learning</li></ul></td></tr><tr><td>Peace Research Institute Oslo</td><td><ul><li>Evaluations by own researchers of academic research (including UCDP), official death statistics, surveys, news reports, and other archival sources<a class="ref" href="#note-13"><sup>13</sup></a></li></ul></td></tr><tr><td>Conflict Catalog</td><td><ul><li>Own evaluations of academic research (including CoW) and other sources</li></ul></td></tr></table> All rely on researchers evaluating independent news reports, academic research, or both. Some also supplement these primary sources with available surveys of the affected populations, or official death statistics. The primary sources they use can partially overlap. Some use the same sources, such as the encyclopedias by Micheal Clodfelter14 Lewis Fry Richardson15, and Pitirim Sorokin16. Or they outright rely on each other as the sources: PRIO and Project Mars use UCDP data, and Project Mars, Militarized Interstate Events, and the Conflict Catalog build on Correlates of War.17 # How do sources work to measure what they want to measure? The next tables summarize how the data sources address the specific challenges of measuring armed conflicts and conflict deaths. The first challenge is to make their assessments valid — to actually measure what they want to measure. <table class="html-table"><tr><td>UCDP</td><td><ul><li>Own researchers know measurement procedures and conflicts well</li><li>Include civilian deaths, as difference to combatants can be blurry</li><li>Exclude deaths due to disease and starvation as well as wounded, as difficult to identify</li></ul></td></tr><tr><td>Project Mars</td><td><ul><li>Own researchers know measurement procedures well</li><li>Exclude civilian deaths, deaths due to disease and starvation, as well as wounded, as interested in military lethality on the battlefield</li></ul></td></tr><tr><td>Militarized Interstate Events</td><td><ul><li>Own researchers know measurement procedures well</li><li>Investigate closely country-pairs with high predicted likelihood of conflict</li></ul></td></tr><tr><td>Correlates of War — War Data</td><td><ul><li>Own researchers know measurement procedures well</li><li>Include deaths due to disease and starvation, as they are integral to war, and often not distinguished from fighting in sources</li><li>Exclude civilian deaths, as difficult to identify</li><li>Sometimes estimate deaths if only number of casualties available</li></ul></td></tr><tr><td>Correlates of War — Militarized Interstate Disputes</td><td><ul><li>Own researchers know measurement procedures well</li><li>Machine learning can process vast numbers of news reports</li><li>Group deaths into broad ranges because number of deaths often uncertain</li></ul></td></tr><tr><td>Peace Research Institute Oslo</td><td><ul><li>Own researchers know measurement procedures well</li><li>Include civilian deaths, as difference to combatants can be blurry</li><li>Exclude deaths due to disease and starvation, as difficult to identify</li></ul></td></tr><tr><td>Conflict Catalog</td><td><ul><li>Own researchers know measurement procedures well</li></ul></td></tr></table> In general, the sources relying on their own researchers have the advantage that these researchers know the respective definitions of armed conflicts and related deaths well and are very familiar with the measurement procedures, which makes it more likely that they code as intended. However, the sources differ in the deaths they include because they weigh the challenges of measurement differently. Some include civilian deaths because they often find it too difficult to distinguish them from combatant deaths. Others exclude them because they find them too difficult to identify comprehensively or because they are only interested in the actions of militaries on the battlefield. Some approaches include deaths due to disease and starvation because they consider them a fundamental part of war, and because primary sources often do not distinguish between them and deaths due to fighting. But others do not, as they find such indirect deaths too challenging to identify comprehensively. Finally, Correlates of War’s war data sometimes estimates the number of deaths based on the number of conflict casualties, if only those are available. And its Militarized Interstate Disputes data mostly groups deaths into broad ranges, as it finds determining more specific numbers too uncertain. # How do sources work to make assessments precise? The sources are also concerned with making their assessments precise and reliable. <table class="html-table"><tr><td>UCDP</td><td><ul><li>Many and different types of sources used</li><li>Not covering earlier years</li><li>Conflicts disaggregated into years and individual events (with at least one death per event)</li><li>Report types of deaths separately</li></ul></td></tr><tr><td>Project Mars</td><td><ul><li>More than 100 researchers split into adversarial teams search at least 10 quality sources per deaths estimate</li><li>Not covering earlier years</li><li>Big and recurrent wars disaggregated into campaigns</li></ul></td></tr><tr><td>Militarized Interstate Events</td><td><ul><li>Many and different types of primary sources used</li><li>Not covering earlier years</li><li>Conflicts disaggregated into years and individual events</li></ul></td></tr><tr><td>Correlates of War — War Data</td><td><ul><li>Many and different types of primary sources used</li><li>Not covering earlier years</li></ul></td></tr><tr><td>Correlates of War — Militarized Interstate Disputes</td><td><ul><li>Many and different types of primary sources used</li><li>Not covering earlier years</li><li>Conflicts partially disaggregated into individual incidents</li></ul></td></tr><tr><td>Peace Research Institute Oslo</td><td><ul><li>Many and different types of sources used</li><li>Not covering earlier years</li><li>Conflicts disaggregated into years</li></ul></td></tr><tr><td>Conflict Catalog</td><td><ul><li>Many and different types of primary sources used</li><li>Not covering earlier years</li><li>Big conflicts disaggregated into smaller ones</li><li>Report types of deaths separately</li></ul></td></tr></table> They all use many primary sources, and most use different types of sources, such as news reports, academic books and articles, or NGO documents. They also all avoid covering conflicts that happened even earlier — even though they differ in how far they think they can go back in time and still have data that is sufficiently reliable: UCDP begins in 1989, whereas the Conflict Catalog starts in the year 1400.18 Several sources also disaggregate their data to make it more precise: they split their estimates of deaths into total, combatant, and civilian deaths, when possible; disaggregate bigger conflicts into smaller ones; or each conflict into years, campaigns, or even specific events. # How do sources work to make assessments comparable? The sources also face the challenge of making the data comparable across conflicts and time. <table class="html-table"><tr><td>UCDP</td><td><ul><li>Researchers have very precise definitions of conflict, deaths, and other event characteristics</li><li>Global news used first, then (sometimes translated) local and specialized sources</li></ul></td></tr><tr><td>Project Mars</td><td><ul><li>Researchers have very precise definitions of conflict and deaths</li><li>Primary sources in 21 languages used</li></ul></td></tr><tr><td>Militarized Interstate Events</td><td><ul><li>Exclude civilian deaths, as they have become more common</li><li>Global news used because more comprehensive</li></ul></td></tr><tr><td>Correlates of War — War Data</td><td><ul><li>Exclude civilian deaths, as they have become more common</li></ul></td></tr><tr><td>Correlates of War — Militarized Interstate Disputes</td><td><ul><li>Exclude civilian deaths, as they have become more common</li><li>Global news used because more comprehensive</li></ul></td></tr><tr><td>Peace Research Institute Oslo</td><td><ul><li>Researchers have precise definitions of conflict and deaths</li></ul></td></tr><tr><td>Conflict Catalog</td><td><ul><li>Also non-English sources used</li></ul></td></tr></table> Some do so by providing their researchers with precise definitions of conflicts and deaths, making it easier to decide which to include. And some also use primary sources in different languages or first identify conflicts and deaths with global sources and then use more local ones. Others, meanwhile, prefer global sources for their more comprehensive coverage of international affairs. # How are the remaining differences between primary sources dealt with? The sources work to address any remaining differences between primary sources, even if they do so differently. <table class="html-table"><tr><td>UCDP</td><td><ul><li>Consider quality of primary sources, discuss within team, use most reliable one</li><li>Provide best, low, and high deaths estimates provided if several plausible</li><li>Use lower as the best estimate if no primary source is more reliable than others; best estimate therefore likely no overcount</li></ul></td></tr><tr><td>Project Mars</td><td><ul><li>Consider quality of primary sources, discuss among coder teams</li><li>Provide low and high estimates</li></ul></td></tr><tr><td>Militarized Interstate Events</td><td><ul><li>Consider quality of primary sources, discuss among coders</li><li>Provide low and high estimates</li></ul></td></tr><tr><td>Correlates of War — War Data</td><td><ul><li>Consider quality of primary sources and context (army size, weapons, medical technology, etc.)</li></ul></td></tr><tr><td>Correlates of War — Militarized Interstate Disputes</td><td><ul><li>Consider quality of primary sources, discuss among coders</li><li>Provide low and high estimates</li><li>Include accusations by targeted state even if denied by allegedly targeting state</li></ul></td></tr><tr><td>Peace Research Institute Oslo</td><td><ul><li>Consider quality of primary sources, use most reliable one</li><li>Provide best, low, and high deaths estimates</li></ul></td></tr><tr><td>Conflict Catalog</td><td><ul><li>Consider quality of primary sources</li></ul></td></tr></table> They all consider the quality of primary sources and prefer more reliable ones. Some also consider the context of the conflicts — such as army size and weapons used — to assess which accounts are more plausible. Others also discuss any discrepancies between researchers on their team. This adds an additional step to make the assessments comparable across coders, conflicts, and time. Correlates of War’s Militarized Interstate Disputes data partially reconciles differences between conflict parties by erring on the side of including accusations by a targeted state even if the state allegedly targeting it denies them. Several approaches provide more than one estimate of conflict deaths and share a low, high, and sometimes also a best estimate. By doing so, they avoid forcing themselves to eliminate all uncertainty and possibly biasing their estimates. UCDP combines these strategies and uses the lower estimate as the best one if no primary source is more reliable than others. It thereby reduces the risk that the estimate overcounts deaths. # How do sources work to make data accessible and transparent? Finally, the data sources all make their data accessible and the underlying measurement transparent. They all publicly release their data, and most make it straightforward to download and use. <table class="html-table"><tr><td>UCDP</td><td><ul><li>Very detailed coding procedures are available and easy to access</li><li>Justifies conflict and death characteristics</li><li>Provides primary source(s) for each event</li><li>Provides context with conflict narratives</li></ul></td></tr><tr><td>Project Mars</td><td><ul><li>Very detailed coding procedures are available and easy to access</li><li>Justifies conflict and death characteristics</li></ul></td></tr><tr><td>Militarized Interstate Events</td><td><ul><li>Detailed coding procedures are available and easy to access</li><li>Justifies conflict and deaths characteristics</li><li>Provides context with conflict narratives</li></ul></td></tr><tr><td>Correlates of War — War Data</td><td><ul><li>Coding procedures are available and partially easy to access</li><li>Justifies conflict and death characteristics</li><li>Provides context with conflict narratives</li></ul></td></tr><tr><td>Correlates of War — Militarized Interstate Disputes</td><td><ul><li>Very detailed coding procedures are available and partially easy to access</li><li>Justifies conflict and deaths characteristics</li><li>Partially provides context with conflict narratives</li></ul></td></tr><tr><td>Peace Research Institute Oslo</td><td><ul><li>Detailed coding procedures are available and easy to access</li><li>Justifies conflict and death characteristics</li></ul></td></tr><tr><td>Conflict Catalog</td><td><ul><li>Coding procedures are available and easy to access</li></ul></td></tr></table> All release descriptions of how they characterize conflicts and deaths and share at least some of the coding procedures guiding the researchers. Militarized Interstate Events and Correlates of War also provide additional helpful information by describing conflicts in accompanying reports. And UCDP shares the primary sources for each event underlying every conflict.19 # The best source depends on your questions There is no single ‘best’ approach to measuring armed conflicts and their deaths. All sources put a lot of effort into measuring conflicts and deaths in ways that are useful to researchers, policymakers, and interested citizens. The most appropriate source depends on what questions you want to answer. It is the one that captures the conflicts, deaths, and time you are interested in. If you are interested in both big and smaller conflicts in recent years, in combatant and civilian deaths, or also non-state conflicts and acts of one-sided violence, UCDP is best. If you are less interested in the most recent years and more in big and smaller conflicts that involve at least one state in the decades since World War II, PRIO data is best. If you also want the most recent years, you can use our combined UCDP+PRIO data.20 If you want to study long-term differences and changes over the last two hundred years and it is sufficient to focus on bigger conflicts, then Project Mars is best. If you are especially interested in specific types of large conflicts over recent centuries, the Correlates of War data is best. If, instead, you want to explore both big and small conflicts between _states_, the Militarized Interstate Events data is best. If you want to explore the source that was researchers’ go-to for interstate conflicts for a long time and are fine with its less precise data, Correlates of War’s Militarized Interstate Disputes data is best. And if you want to study bigger conflicts over more than the last half millennium and are willing to accept lower data quality, the Conflict Catalog is best. This means that having several approaches to measuring conflict deaths is not a flaw but a strength: it gives us different tools to understand the past, current state, and possible future of armed conflict around the world. If you want to explore and compare the data that each dataset produces, you can do so in our work on [War and Peace](https://docs.google.com/document/d/1fdECw4wt6d7_-cIeMcsBfnoUEoeKwF2Z1gj3Y8RCF4g/edit) and in our [Conflict Data Explorers](https://docs.google.com/document/d/1SpyofFwtTSpD69fW6rUq-D-zM6DSsW7I7l0_bNC-AMA/edit). <Callout title="Acknowledgements"/> ## Keep reading at Our World in Data ### undefined undefined https://docs.google.com/document/d/1H_dmh_1YYoY605lcVHtyOm2RZ2AfpIUuimG99ubmcHs/edit ### undefined undefined https://docs.google.com/document/d/1SpyofFwtTSpD69fW6rUq-D-zM6DSsW7I7l0_bNC-AMA/edit Davies, Shawn, Therese Pettersson, and Magnus Öberg. 2023. Organized violence 1989-2022 and the return of conflicts between states? Journal of Peace Research 60(4): 691-708. Gleditsch, Nils Petter, Peter Wallensteen, Mikael Eriksson, Margareta Sollenberg, and Håvard Strand. 2002. [Armed conflict 1946–2001: A new dataset](https://journals.sagepub.com/doi/10.1177/0022343302039005007). Journal of Peace Research 39(5): 615–637. Gibler, Douglas, and Steven Miller. 2023. [The Militarized Interstate Confrontation Dataset, 1816-2014](https://journals.sagepub.com/doi/abs/10.1177/00220027221104704). Journal of Conflict Resolution. OnlineFirst. Gibler, Douglas, and Steven Miller. 2023. [The Militarized Interstate Events (MIE) dataset, 1816–2014](https://journals.sagepub.com/doi/abs/10.1177/07388942231182674). Conflict Management and Peace Science. OnlineFirst. Sarkees, Meredith Reid, and Frank Wayman. 2010. [Resort to War: A Data Guide to Inter-State, Extra-State, Intra-State, and Non-State Wars, 1816-2007](https://archive.org/details/resorttowardatag0000sark/page/450/mode/2up). CQ Press. Palmer, Glenn, Roseanne McManus, Vito D’Orazio, Michael Kenwick, Mikaela Karstens, Chase Bloch, Nick Dietrich, Kayla Kahn, Kellan Ritter, and Michael Soules. 2021. [The MID5 Dataset, 2011-2014: Procedures, coding rules, and description](https://journals.sagepub.com/doi/full/10.1177/0738894221995743). Conflict Management and Peace Science 38(5): 470-482. While UCDP and PRIO cover the same deaths and partially the same conflicts, their different sources often lead to somewhat different estimates: UCDP collects data on deaths for each individual conflict event, whereas PRIO uses less specific summary estimates. UCDP also looks at non-state conflicts and one-sided violence, which PRIO does not. Yet, PRIO’s summary estimates may still partially include deaths from non-state conflicts or one-sided violence that are closely tied to the state-based conflicts it covers. UCDP only includes an event if it can identify the perpetrator. Because PRIO does not look at events, its summary estimates may partially include deaths where a likely perpetrator was identified as likely, but not conclusively determined. These differences explain why UCDP tends to report fewer deaths than PRIO. The joint UCDP and PRIO report [Estimating Battle Deaths: A Challenging Exercise](https://www.pcr.uu.se/digitalAssets/666/c_666984-l_1-k_hsrp_est.battle_deaths_1.2.13.pdf) discusses this further. Lyall, Jason. 2020. [Divided Armies: Inequality and Battlefield Performance in Modern War](https://press.princeton.edu/books/paperback/9780691192444/divided-armies). Princeton University Press. Lacina, Bethany, and Nils Petter Gleditsch. 2005. [Monitoring Trends in Global Combat: A New Dataset of Battle Deaths](https://link.springer.com/article/10.1007/s10680-005-6851-6). European Journal of Population 21: 145-166. Brecke, Peter. 1999. [Violent Conflicts 1400 A.D. to the Present in Different Regions of the World](https://cpn-us-w2.wpmucdn.com/sites.gatech.edu/dist/1/19/files/2018/09/Brecke-PSS-1999-paper-Violent-Conflicts-1400-AD-to-the-Present.pdf). Paper prepared for the 1999 Meeting of the Peace Science Society (International) on October 8-10, 1999 in Ann Arbor, Michigan. This article draws on several helpful other articles summarizing and reviewing some of the datasets, as well as the datasets’ codebooks and descriptions: Brecke, Peter. 1999. [Violent Conflicts 1400 A.D. to the Present in Different Regions of the World](https://cpn-us-w2.wpmucdn.com/sites.gatech.edu/dist/1/19/files/2018/09/Brecke-PSS-1999-paper-Violent-Conflicts-1400-AD-to-the-Present.pdf). Paper prepared for the 1999 Meeting of the Peace Science Society (International) on October 8-10, 1999 in Ann Arbor, Michigan. Brecke, Peter. 2012. [Notes regarding the Conflict Catalog](http://www.cgeh.nl/sites/default/files/Notes%20about%20Conflict%20Catalog.pdf). Eck, Kristine, and Lisa Hultman. 2007. [One-sided violence against civilians in war: insights from new fatality data](https://journals.sagepub.com/doi/10.1177/0022343307075124). Journal of Peace Research 44(2): 233-246. Gleditsch, Nils Petter, Peter Wallensteen, Mikael Eriksson, Margareta Sollenberg, and Håvard Strand. 2002. [Armed conflict 1946–2001: A new dataset](https://journals.sagepub.com/doi/10.1177/0022343302039005007). Journal of Peace Research 39(5): 615–637. Gibler, Douglas, and Steven Miller. 2022. [An Appraisal of Project Mars and the Divided Armies Argument](https://academic.oup.com/isq/article-abstract/66/2/sqac011/6569150?redirectedFrom=fulltext). International Studies Quarterly 66(2): 1-9. Gibler, Douglas, and Steven Miller. 2023. [The Militarized Interstate Confrontation Dataset, 1816-2014](https://journals.sagepub.com/doi/abs/10.1177/00220027221104704). Journal of Conflict Resolution. OnlineFirst. Gibler, Douglas, and Steven Miller. 2023. [The Militarized Interstate Events (MIE) dataset, 1816–2014](https://journals.sagepub.com/doi/abs/10.1177/07388942231182674). Conflict Management and Peace Science. OnlineFirst. Gohdes, Anita, and Megan Price. 2012. [First Things First: Assessing Data Quality before Model Quality](https://journals.sagepub.com/doi/abs/10.1177/0022002712459708). Journal of Conflict Resolution 57(6): 1090-1108. Högbladh, Stina. 2022. [UCDP Georeferenced Event Dataset Codebook Version 22.1](https://ucdp.uu.se/downloads/ged/ged221.pdf). Jones, Daniel, Stuart Bremer, and J. David Singer. 1996. [Militarized Interstate Disputes, 1816-1992: Rationale, Coding Rules, and Empirical Patterns](https://journals.sagepub.com/doi/10.1177/073889429601500203). Conflict Management and Peace Science 15(2): 163-213. Palmer, Glenn, Roseanne McManus, Vito D’Orazio, Michael Kenwick, Mikaela Karstens, Chase Bloch, Nick Dietrich, Kayla Kahn, Kellan Ritter, and Michael Soules. 2021. [The MID5 Dataset, 2011-2014: Procedures, coding rules, and description](https://journals.sagepub.com/doi/full/10.1177/0738894221995743). Conflict Management and Peace Science 38(5): 470-482. Palmer, Glenn, Vito D’Orazio, Michael Kenwick, and Matthew Lane. 2015. [The MID4 dataset, 2002-2010: Procedures, coding rules and description](https://journals.sagepub.com/doi/10.1177/0738894214559680). Conflict Management and Peace Science 32(2): 222-242. Lacina, Bethany. 2009. [Battle Deaths Dataset 1946–2008](https://www.prio.org/data/1). Codebook for Version 3.0. Lacina, Bethany, and Nils Petter Gleditsch. 2005. [Monitoring Trends in Global Combat: A New Dataset of Battle Deaths](https://link.springer.com/article/10.1007/s10680-005-6851-6). European Journal of Population 21: 145-166. Lacina, Bethany, and Nils Petter Gledtisch. 2012. [The Waning of War is Real: A Response to Gohdes and Price](https://journals.sagepub.com/doi/abs/10.1177/0022002712459709). Journal of Conflict Resolution 57(6): 1109-1127. Lyall, Jason. 2022. [Sources, Data, Methods: The Project Mars Codebook Version 1.1](https://dataverse.harvard.edu/dataset.xhtml?persistentId=doi:10.7910/DVN/DUO7IE). Pettersson, Therese. 2022a. [UCDP Battle-related Deaths Dataset Codebook v 22.1](https://ucdp.uu.se/downloads/brd/ucdp-brd-codebook-221.pdf). Pettersson, Therese. 2022b. [UCDP Non-state Conflict Codebook v 22.1](https://ucdp.uu.se/downloads/nsos/ucdp-nonstate-221.pdf). Pettersson, Therese. 2022c. [UCDP One-sided Violence Codebook v 22.1](https://ucdp.uu.se/downloads/nsos/ucdp-onesided-221.pdf). Sarkees, Meredith Reid, and Frank Wayman. 2010. [Resort to War: A Data Guide to Inter-State, Extra-State, Intra-State, and Non-State Wars, 1816-2007](https://archive.org/details/resorttowardatag0000sark/page/450/mode/2up). CQ Press. Spagat, Michael, Brennen Fagan, and Stijn Van Weezel. 2022. From Gaddis to Mars: The Decline of War Enters New Territory. Working Paper. Sundberg, Ralph, Kristine Eck, and Joakim Kreutz. 2012. [Introducing the UCDP Non-State Conflict Dataset](https://journals.sagepub.com/doi/abs/10.1177/0022343311431598). Journal of Peace Research 49(2): 351-362. UCDP also includes a conflict with fewer than 25 deaths in a year when it has passed this threshold at least once. But they consider such a conflict to be inactive. Project Mars formally only includes interstate conflicts, but de facto includes intrastate and extrastate conflicts because it has a broader definition of what armed groups are considered states: conflicts in which combatants are fighting over governing a state they both claim authority over can still be included. Correlates of War labels these conflicts as intra-state if they happen within one state’s territory Sometimes, however, these terms are used interchangeably. This becomes a challenge for researchers trying to identify the specific human toll of a conflict. We discuss how deaths from terrorism are identified in [our article](https://docs.google.com/document/d/1ADv-Q76wuEHYOuCCf4oI-pqU4rBM7FXo_kMGR267tm0/edit) on the Global Terrorism Database. Clodfelter, Micheal. 2017. Warfare and Armed Conflicts: A Statistical Encyclopedia of Casualty and other Figures, 1492-2015. Fourth edition. McFarland & Company. Richardson, Lewis Fry. 1960. Statistics of Deadly Quarrels. Boxwood Press. Sorokin, Pitirim. 1937. Social and cultural dynamics. Volume Three: Fluctuation of Social Relationships, War, and Revolution. American Book Company. The Institute for Health Metrics and Evaluation’s Global Burden of Disease also partially relies on UCDP to calculate its estimates of [deaths from conflict and terrorism](https://ourworldindata.org/grapher/death-rates-from-conflict-and-terrorism-gbd?country=~AFG). Peter Brecke, who assembled the Conflict Catalog, himself emphasizes that both the conflicts and the deaths included are incomplete, particularly for the distant past and outside of Europe. Militarized Interstate Events has plans to share the source(s) for each of its events. For example, here are [deaths in state-based conflicts by region](https://ourworldindata.org/grapher/deaths-in-state-based-conflicts-by-region) and [deaths in state-based conflict by conflict type](https://ourworldindata.org/grapher/deaths-in-state-based-conflicts-by-type).	How major sources collect data on conflicts and conflict deaths, and when to use which one

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{
    "toc": [
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            "slug": "keep-reading-at-our-world-in-data",
            "text": "Keep reading at Our World in Data",
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    "body": [
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                        {
                            "text": "Explore the data discussed in this article in our work on ",
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                                    "text": "War and Peace",
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                            "text": " and our ",
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                                    "text": "Conflict Data Explorers",
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                        {
                            "text": ", and read more about its measures in ",
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                            "url": "https://docs.google.com/document/d/1H_dmh_1YYoY605lcVHtyOm2RZ2AfpIUuimG99ubmcHs/edit",
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                                    "text": "our article on them",
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                            "text": ".",
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            "type": "callout",
            "title": "More on conflict data",
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                    "text": "Measuring armed conflicts and conflict deaths across the world helps us understand how people\u2019s lives and livelihoods are affected by large-scale violence.",
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                    "text": "But this comes with many challenges. People do not always agree on what characteristics define an armed conflict. Even once defined, these characteristics \u2014 especially how many people died in them \u2014 are difficult to assess.",
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                    "text": "The people affected are not always asked who has died around them due to the conflict.",
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            "value": [
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                    "text": "The conflict parties may underreport deaths to claim success, or overreport them to encourage intervention by third parties.",
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                    "text": "Independent observers may also struggle to be present in all places and document a conflict\u2019s death toll.",
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                    "text": "So how do researchers address these challenges?",
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                    "text": "In our work on ",
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                    "url": "https://ourworldindata.org/war-and-peace",
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                            "text": "War and Peace",
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                    "text": ", we provide data from six sources that identify armed conflicts and count their deaths:",
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                            "text": "Uppsala Conflict Data Program (UCDP)",
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                            "url": "#note-1",
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                                    "children": [
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                                            "text": "1",
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                            "text": "Project Mars by Jason Lyall (2022)",
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                            "url": "#note-2",
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                                            "text": "2",
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                            "text": "Militarized Interstate Events by Douglas Gibler and Steven Miller",
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                            "url": "#note-3",
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                                            "text": "3",
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                            "text": "Correlates of War (CoW)",
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                            "url": "#note-4",
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                                            "text": "4",
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                            "text": "Peace Research Institute Oslo (PRIO)",
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                            "url": "#note-5",
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                                            "text": "5",
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                            "text": "Conflict Catalog by Peter Brecke (1999)",
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                            "url": "#note-6",
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                                            "text": "6",
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                    "text": "These sources all measure armed conflicts and their deaths; they cover many countries and years, and researchers and policymakers frequently use them.",
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                    "text": "In our ",
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                    "url": "https://docs.google.com/document/d/1SpyofFwtTSpD69fW6rUq-D-zM6DSsW7I7l0_bNC-AMA/edit",
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                            "text": "Conflict Data Explorers",
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                {
                    "text": ", you can delve into global and regional overviews of conflicts and their deaths.",
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                    "text": "Reassuringly, sources typically agree about big differences in the deaths from armed conflicts: they readily distinguish between deadly and peaceful years.",
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                    "text": "But they do not always agree. They often come to different assessments about ",
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                            "text": "how ",
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                    "text": "widespread and deadly some years were.",
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                    "text": "Why do these sources arrive at different numbers? And is there any best approach?",
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                    "text": "I summarize the key similarities and differences between the different approaches in this article and when to use which one.",
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            "text": [
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                    "text": "What conflicts are covered?",
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                    "text": "In this table and the ones that follow, I summarize what armed conflicts and conflict deaths each data source covers.",
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                {
                    "url": "#note-7",
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                                    "text": "7",
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            "value": "<table class=\"html-table\"><tr><td>UCDP</td><td><ul><li>Armed conflicts: interstate, intrastate, extrastate, non-state, and one-sided violence</li><li>At least 25 deaths during a year (based on most plausible estimate)<a class=\"ref\" href=\"#note-8\"><sup>8</sup></a></li></ul></td></tr><tr><td>Project Mars</td><td><ul><li>Conventional wars: interstate; de facto also intrastate and extrastate</li><li>At least 500 deaths (based on highest plausible estimate)</li><li>Primary combatants have differentiated militaries, and clear frontlines</li></ul></td></tr><tr><td>Militarized Interstate Events</td><td><ul><li>Militarized interstate confrontations: interstate threats of force, display of force, use of force, war</li></ul></td></tr><tr><td>Correlates of War \u2014 Wars</td><td><ul><li>Wars: interstate, intrastate, extrastate, and non-state</li><li>At least 1,000 deaths during a year</li></ul></td></tr><tr><td>Correlates of War \u2014 Militarized Interstate Disputes</td><td><ul><li>Militarized interstate disputes: interstate threats of force, display of force, use of force, war</li><li>At least use of force threatened</li><li>At least 1,000 deaths during a year for war</li></ul></td></tr><tr><td>Peace Research Institute Oslo</td><td><ul><li>Armed conflicts: interstate, intrastate, and extrastate</li><li>At least 25 deaths during a year</li></ul></td></tr><tr><td>Conflict Catalog</td><td><ul><li>Violent political conflicts: interstate, intrastate, extrastate, non-state and one-sided violence</li><li>At least 32 deaths during a year</li></ul></td></tr></table>",
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                    "text": "All sources characterize an armed conflict as a disagreement between organized groups that involves force. For most datasets, this means that force is used. But for the Militarized Interstate Events data and Correlates of War\u2019s Militarized Interstate Disputes data, this can also mean that force is threatened or displayed.",
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                    "text": "Approaches also differ in what types of conflicts they cover and how many deaths they must cause to be included.",
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                    "text": "They all include armed conflicts where the primary combatants are states (interstate conflicts), and most cover those conflicts between a state and an armed group that is not a state inside the state\u2019s territory (intrastate conflicts) or outside the state\u2019s territory (extrastate conflicts).",
                    "spanType": "span-simple-text"
                },
                {
                    "url": "#note-9",
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                            "children": [
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                                    "text": "9",
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                    "text": " These conflicts are sometimes grouped together as \u201cstate-based\u201d conflicts.",
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                    "text": "Some approaches go further and also include conflicts where neither armed group is a state (non-state conflicts). ",
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                {
                    "url": "#note-10",
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                            "children": [
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                                    "text": "10",
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                {
                    "text": " And some even include violence by an armed group \u2014 state or non-state \u2014 against civilians (one-sided violence).",
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                    "text": "Most sources only include conflicts if they cause many deaths. Some set a threshold of at least 500 or 1,000 annual or total deaths, and then call these deadly conflicts ",
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                    "children": [
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                            "text": "wars",
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                    "text": ". Others include more minor armed conflicts that cause a few dozen deaths during a year. And the Militarized Interstate Events data and Correlates of War\u2019s Militarized Interstate Disputes data also include conflicts in which no one died.",
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                    "text": "Finally, the specific definitions of the sources mean that their conflicts differ slightly beyond their differences in conflict type and death toll. The biggest of these minor differences is that Project Mars only includes conventional wars, those fought between differentiated militaries along clear frontlines. Others do not make such a distinction.",
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            "text": [
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                    "text": "Which deaths are included?",
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                    "text": "The data sources also differ in who they include in their death counts and how they were killed.",
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            "value": "<table class=\"html-table\"><tr><td>UCDP</td><td><ul><li>Total, combatant, and civilian deaths, due to fighting</li></ul></td></tr><tr><td>Project Mars</td><td><ul><li>Deaths of combatants, due to fighting</li></ul></td></tr><tr><td>Militarized Interstate Events</td><td><ul><li>Deaths of combatants, due to fighting</li></ul></td></tr><tr><td>Correlates of War \u2014 War Data</td><td><ul><li>Deaths of combatants, due to fighting, disease, and starvation</li></ul></td></tr><tr><td>Correlates of War \u2014 Militarized Interstate Disputes</td><td><ul><li>Deaths of combatants, due to fighting</li></ul></td></tr><tr><td>Peace Research Institute Oslo</td><td><ul><li>Deaths of combatants and civilians, due to fighting</li></ul></td></tr><tr><td>Conflict Catalog</td><td><ul><li>Total, combatant, and civilian deaths, due to fighting, disease, and starvation</li></ul></td></tr></table>",
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                    "text": "All sources record deaths, the people killed in the conflict. This is different from other sources which record casualties, which include both deaths and those wounded. Yet other sources even tally losses, including both casualties and those deserted.",
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                    "url": "#note-11",
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                                    "text": "11",
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                    "text": "But some approaches only include deaths of combatants \u2014 those doing the fighting. Others also include civilians \u2014 those who do not take up any weapons but may be killed accidentally or intentionally (in cases of one-sided violence).",
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                    "text": "These civilian deaths also include victims of terrorist attacks, as long as the attack was carried out by an armed group.",
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                    "url": "#note-12",
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                                    "text": "12",
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                    "text": "And some approaches only include direct, or battle-related, deaths \u2014 those due to the fighting. Meanwhile, others include direct and indirect, or war-related, deaths \u2014 both those due to fighting, and those due to disease or starvation caused by the conflict.",
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            "text": [
                {
                    "text": "What years and countries are covered?",
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            "type": "heading",
            "level": 1,
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            "type": "text",
            "value": [
                {
                    "text": "All data sources provide historical data and cover conflicts worldwide. But they differ in what years they cover, and which countries and regions they consider sovereign states.",
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                }
            ],
            "parseErrors": []
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            "type": "html",
            "value": "<table class=\"html-table\"><tr><td>UCDP</td><td><ul><li>1989 \u2014 ongoing</li><li>Global</li></ul></td></tr><tr><td>Project Mars</td><td><ul><li>1800 \u2014 2011 / ongoing</li><li>Global</li></ul></td></tr><tr><td>Militarized Interstate Events</td><td><ul><li>1816 \u2014 2014 / ongoing</li><li>Global</li></ul></td></tr><tr><td>Correlates of War \u2014 War Data</td><td><ul><li>1816 \u2014 2007 (extrastate, non-state), 1816 \u2014 2010 (inter-state), 1816 \u2014 2014 (intrastate) / ongoing</li><li>Global</li></ul></td></tr><tr><td>Correlates of War \u2014 Militarized Interstate Disputes</td><td><ul><li>1816 \u2014 2014 / ongoing</li><li>Global</li></ul></td></tr><tr><td>Peace Research Institute Oslo</td><td><ul><li>1946 \u2014 2008</li><li>Global</li></ul></td></tr><tr><td>Conflict Catalog</td><td><ul><li>1400 \u2014 2000</li><li>Global</li></ul></td></tr></table>",
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            "type": "text",
            "value": [
                {
                    "text": "UCDP currently provides the most recent data, as it is updated each year. Other sources are updated less frequently and currently have a delay of about a decade on their most recent data (Project Mars, Militarized Interstate Events, and Correlates of War), or they are no longer maintained and will likely not be updated for recent decades (Conflict Catalog and PRIO).",
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            "value": [
                {
                    "text": "In turn, UCDP only begins at the end of the Cold War. In contrast, the other sources start in the mid- or early 20th century (PRIO), the early 19th century (Project Mars, Militarized Interstate Events, and Correlates of War), or even reach as far back in time as the year 1400 (Conflict Catalog).",
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            "value": [
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                    "text": "The data sources also differ in which countries and regions they consider sovereign states. Correlates of War and Militarized Interstate Events use the state system by ",
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                    "url": "https://ourworldindata.org/grapher/sovereign-state-cow",
                    "children": [
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                            "text": "Correlates of War",
                            "spanType": "span-simple-text"
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                    "spanType": "span-link"
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                {
                    "text": ", which until 1919 requires diplomatic recognition by France and the United Kingdom for a country to be included.",
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            "value": [
                {
                    "text": "UCDP and PRIO meanwhile use the slightly more inclusive list of sovereign states by ",
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                {
                    "url": "https://ourworldindata.org/grapher/sovereign-state-gleditsch-ward",
                    "children": [
                        {
                            "text": "Gleditsch and Ward",
                            "spanType": "span-simple-text"
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                    ],
                    "spanType": "span-link"
                },
                {
                    "text": ". Project Mars and the Conflict Catalog have even more expansive definitions of statehood, and are closer to the state system as identified by ",
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                },
                {
                    "url": "https://ourworldindata.org/grapher/sovereign-state-butcher-griffiths",
                    "children": [
                        {
                            "text": "Butcher and Griffiths",
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                    "spanType": "span-link"
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                {
                    "text": ".",
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            "value": [
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                    "text": "This affects how some conflicts are classified, as an extrastate or non-state war in Correlates of War\u2019s war data can be classified as an interstate or civil war in Project Mars. And it affects how conflict rates are ",
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                {
                    "url": "https://docs.google.com/document/d/1H_dmh_1YYoY605lcVHtyOm2RZ2AfpIUuimG99ubmcHs/edit",
                    "children": [
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                            "text": "calculated",
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                    ],
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                {
                    "text": ", as the number of countries for each year can ",
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                {
                    "url": "https://ourworldindata.org/grapher/number-of-countries",
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                            "text": "differ a lot",
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                    ],
                    "spanType": "span-link"
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                {
                    "text": ", ",
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                    "url": "https://ourworldindata.org/grapher/number-of-countries-by-region",
                    "children": [
                        {
                            "text": "especially",
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                {
                    "text": " for Africa and Asia and Oceania.",
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        {
            "text": [
                {
                    "text": "How are conflicts and deaths identified?",
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            ],
            "type": "heading",
            "level": 1,
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            "value": [
                {
                    "text": "Generally, the data sources are similar in how they go about assessing conflicts and the deaths in them.",
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        },
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            "value": "<table class=\"html-table\"><tr><td>UCDP</td><td><ul><li>Evaluations by own researchers of news reports, other contemporary sources, and academic research</li></ul></td></tr><tr><td>Project Mars</td><td><ul><li>Evaluations by own researchers of academic research (including UCDP and CoW), news reports, and other contemporary sources</li></ul></td></tr><tr><td>Militarized Interstate Events</td><td><ul><li>Evaluations by own researchers of academic research (including CoW) and news reports, other contemporary sources, and academic research</li></ul></td></tr><tr><td>Correlates of War \u2014 War Data</td><td><ul><li>Evaluations by own researchers of academic research</li></ul></td></tr><tr><td>Correlates of War \u2014 Militarized Interstate Disputes</td><td><ul><li>Evaluations by own researchers of academic research and news reports filtered by machine learning</li></ul></td></tr><tr><td>Peace Research Institute Oslo</td><td><ul><li>Evaluations by own researchers of academic research (including UCDP), official death statistics, surveys, news reports, and other archival sources<a class=\"ref\" href=\"#note-13\"><sup>13</sup></a></li></ul></td></tr><tr><td>Conflict Catalog</td><td><ul><li>Own evaluations of academic research (including CoW) and other sources</li></ul></td></tr></table>",
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            "type": "text",
            "value": [
                {
                    "text": "All rely on researchers evaluating independent news reports, academic research, or both. Some also supplement these primary sources with available surveys of the affected populations, or official death statistics.",
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                {
                    "text": "The primary sources they use can partially overlap. Some use the same sources, such as the encyclopedias by Micheal Clodfelter",
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                },
                {
                    "url": "#note-14",
                    "children": [
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                            "children": [
                                {
                                    "text": "14",
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                                }
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                            "spanType": "span-superscript"
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                    "spanType": "span-ref"
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                {
                    "text": " Lewis Fry Richardson",
                    "spanType": "span-simple-text"
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                {
                    "url": "#note-15",
                    "children": [
                        {
                            "children": [
                                {
                                    "text": "15",
                                    "spanType": "span-simple-text"
                                }
                            ],
                            "spanType": "span-superscript"
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                    "spanType": "span-ref"
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                {
                    "text": ", and Pitirim Sorokin",
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                },
                {
                    "url": "#note-16",
                    "children": [
                        {
                            "children": [
                                {
                                    "text": "16",
                                    "spanType": "span-simple-text"
                                }
                            ],
                            "spanType": "span-superscript"
                        }
                    ],
                    "spanType": "span-ref"
                },
                {
                    "text": ". Or they outright rely on each other as the sources: PRIO and Project Mars use UCDP data, and Project Mars, Militarized Interstate Events, and the Conflict Catalog build on Correlates of War.",
                    "spanType": "span-simple-text"
                },
                {
                    "url": "#note-17",
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                            "children": [
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                                    "text": "17",
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        {
            "text": [
                {
                    "text": "How do sources work to measure what they want to measure?",
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            "type": "heading",
            "level": 1,
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            "type": "text",
            "value": [
                {
                    "text": "The next tables summarize how the data sources address the specific challenges of measuring armed conflicts and conflict deaths. The first challenge is to make their assessments valid \u2014 to actually measure what they want to measure.",
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            "value": "<table class=\"html-table\"><tr><td>UCDP</td><td><ul><li>Own researchers know measurement procedures and conflicts well</li><li>Include civilian deaths, as difference to combatants can be blurry</li><li>Exclude deaths due to disease and starvation as well as wounded, as difficult to identify</li></ul></td></tr><tr><td>Project Mars</td><td><ul><li>Own researchers know measurement procedures well</li><li>Exclude civilian deaths, deaths due to disease and starvation, as well as wounded, as interested in military lethality on the battlefield</li></ul></td></tr><tr><td>Militarized Interstate Events</td><td><ul><li>Own researchers know measurement procedures well</li><li>Investigate closely country-pairs with high predicted likelihood of conflict</li></ul></td></tr><tr><td>Correlates of War \u2014 War Data</td><td><ul><li>Own researchers know measurement procedures well</li><li>Include deaths due to disease and starvation, as they are integral to war, and often not distinguished from fighting in sources</li><li>Exclude civilian deaths, as difficult to identify</li><li>Sometimes estimate deaths if only number of casualties available</li></ul></td></tr><tr><td>Correlates of War \u2014 Militarized Interstate Disputes</td><td><ul><li>Own researchers know measurement procedures well</li><li>Machine learning can process vast numbers of news reports</li><li>Group deaths into broad ranges because number of deaths often uncertain</li></ul></td></tr><tr><td>Peace Research Institute Oslo</td><td><ul><li>Own researchers know measurement procedures well</li><li>Include civilian deaths, as difference to combatants can be blurry</li><li>Exclude deaths due to disease and starvation, as difficult to identify</li></ul></td></tr><tr><td>Conflict Catalog</td><td><ul><li>Own researchers know measurement procedures well</li></ul></td></tr></table>",
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            "value": [
                {
                    "text": "In general, the sources relying on their own researchers have the advantage that these researchers know the respective definitions of armed conflicts and related deaths well and are very familiar with the measurement procedures, which makes it more likely that they code as intended.",
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                    "text": "However, the sources differ in the deaths they include because they weigh the challenges of measurement differently. Some include civilian deaths because they often find it too difficult to distinguish them from combatant deaths.",
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                    "text": "Others exclude them because they find them too difficult to identify comprehensively or because they are only interested in the actions of militaries on the battlefield.",
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                    "text": "Some approaches include deaths due to disease and starvation because they consider them a fundamental part of war, and because primary sources often do not distinguish between them and deaths due to fighting. But others do not, as they find such indirect deaths too challenging to identify comprehensively.",
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                    "text": "Finally, Correlates of War\u2019s war data sometimes estimates the number of deaths based on the number of conflict casualties, if only those are available. And its Militarized Interstate Disputes data mostly groups deaths into broad ranges, as it finds determining more specific numbers too uncertain.",
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            "text": [
                {
                    "text": "How do sources work to make assessments precise?",
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                    "text": "The sources are also concerned with making their assessments precise and reliable.",
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            "value": "<table class=\"html-table\"><tr><td>UCDP</td><td><ul><li>Many and different types of sources used</li><li>Not covering earlier years</li><li>Conflicts disaggregated into years and individual events (with at least one death per event)</li><li>Report types of deaths separately</li></ul></td></tr><tr><td>Project Mars</td><td><ul><li>More than 100 researchers split into adversarial teams search at least 10 quality sources per deaths estimate</li><li>Not covering earlier years</li><li>Big and recurrent wars disaggregated into campaigns</li></ul></td></tr><tr><td>Militarized Interstate Events</td><td><ul><li>Many and different types of primary sources used</li><li>Not covering earlier years</li><li>Conflicts disaggregated into years and individual events</li></ul></td></tr><tr><td>Correlates of War \u2014 War Data</td><td><ul><li>Many and different types of primary sources used</li><li>Not covering earlier years</li></ul></td></tr><tr><td>Correlates of War \u2014 Militarized Interstate Disputes</td><td><ul><li>Many and different types of primary sources used</li><li>Not covering earlier years</li><li>Conflicts partially disaggregated into individual incidents</li></ul></td></tr><tr><td>Peace Research Institute Oslo</td><td><ul><li>Many and different types of sources used</li><li>Not covering earlier years</li><li>Conflicts disaggregated into years</li></ul></td></tr><tr><td>Conflict Catalog</td><td><ul><li>Many and different types of primary sources used</li><li>Not covering earlier years</li><li>Big conflicts disaggregated into smaller ones</li><li>Report types of deaths separately</li></ul></td></tr></table>",
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            "type": "text",
            "value": [
                {
                    "text": "They all use many primary sources, and most use different types of sources, such as news reports, academic books and articles, or NGO documents.",
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                    "text": "They also all avoid covering conflicts that happened even earlier \u2014 even though they differ in how far they think they can go back in time and still have data that is sufficiently reliable: UCDP begins in 1989, whereas the Conflict Catalog starts in the year 1400.",
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                    "url": "#note-18",
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                                    "text": "18",
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                    "text": "Several sources also disaggregate their data to make it more precise: they split their estimates of deaths into total, combatant, and civilian deaths, when possible; disaggregate bigger conflicts into smaller ones; or each conflict into years, campaigns, or even specific events.",
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            "text": [
                {
                    "text": "How do sources work to make assessments comparable?",
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                    "text": "The sources also face the challenge of making the data comparable across conflicts and time.",
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            "value": "<table class=\"html-table\"><tr><td>UCDP</td><td><ul><li>Researchers have very precise definitions of conflict, deaths, and other event characteristics</li><li>Global news used first, then (sometimes translated) local and specialized sources</li></ul></td></tr><tr><td>Project Mars</td><td><ul><li>Researchers have very precise definitions of conflict and deaths</li><li>Primary sources in 21 languages used</li></ul></td></tr><tr><td>Militarized Interstate Events</td><td><ul><li>Exclude civilian deaths, as they have become more common</li><li>Global news used because more comprehensive</li></ul></td></tr><tr><td>Correlates of War \u2014 War Data</td><td><ul><li>Exclude civilian deaths, as they have become more common</li></ul></td></tr><tr><td>Correlates of War \u2014 Militarized Interstate Disputes</td><td><ul><li>Exclude civilian deaths, as they have become more common</li><li>Global news used because more comprehensive</li></ul></td></tr><tr><td>Peace Research Institute Oslo</td><td><ul><li>Researchers have precise definitions of conflict and deaths</li></ul></td></tr><tr><td>Conflict Catalog</td><td><ul><li>Also non-English sources used</li></ul></td></tr></table>",
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                    "text": "Some do so by providing their researchers with precise definitions of conflicts and deaths, making it easier to decide which to include.",
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                    "text": "And some also use primary sources in different languages or first identify conflicts and deaths with global sources and then use more local ones. Others, meanwhile, prefer global sources for their more comprehensive coverage of international affairs.",
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            "text": [
                {
                    "text": "How are the remaining differences between primary sources dealt with?",
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                    "text": "The sources work to address any remaining differences between primary sources, even if they do so differently.",
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            "value": "<table class=\"html-table\"><tr><td>UCDP</td><td><ul><li>Consider quality of primary sources, discuss within team, use most reliable one</li><li>Provide best, low, and high deaths estimates provided if several plausible</li><li>Use lower as the best estimate if no primary source is more reliable than others; best estimate therefore likely no overcount</li></ul></td></tr><tr><td>Project Mars</td><td><ul><li>Consider quality of primary sources, discuss among coder teams</li><li>Provide low and high estimates</li></ul></td></tr><tr><td>Militarized Interstate Events</td><td><ul><li>Consider quality of primary sources, discuss among coders</li><li>Provide low and high estimates</li></ul></td></tr><tr><td>Correlates of War \u2014 War Data</td><td><ul><li>Consider quality of primary sources and context (army size, weapons, medical technology, etc.)</li></ul></td></tr><tr><td>Correlates of War \u2014 Militarized Interstate Disputes</td><td><ul><li>Consider quality of primary sources, discuss among coders</li><li>Provide low and high estimates</li><li>Include accusations by targeted state even if denied by allegedly targeting state</li></ul></td></tr><tr><td>Peace Research Institute Oslo</td><td><ul><li>Consider quality of primary sources, use most reliable one</li><li>Provide best, low, and high deaths estimates</li></ul></td></tr><tr><td>Conflict Catalog</td><td><ul><li>Consider quality of primary sources</li></ul></td></tr></table>",
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                    "text": "They all consider the quality of primary sources and prefer more reliable ones. Some also consider the context of the conflicts \u2014 such as army size and weapons used \u2014 to assess which accounts are more plausible.",
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                    "text": "Others also discuss any discrepancies between researchers on their team. This adds an additional step to make the assessments comparable across coders, conflicts, and time.",
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            "value": [
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                    "text": "Correlates of War\u2019s Militarized Interstate Disputes data partially reconciles differences between conflict parties by erring on the side of including accusations by a targeted state even if the state allegedly targeting it denies them.",
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                    "text": "Several approaches provide more than one estimate of conflict deaths and share a low, high, and sometimes also a best estimate. By doing so, they avoid forcing themselves to eliminate all uncertainty and possibly biasing their estimates.",
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                    "text": "UCDP combines these strategies and uses the lower estimate as the best one if no primary source is more reliable than others. It thereby reduces the risk that the estimate overcounts deaths.",
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            "text": [
                {
                    "text": "How do sources work to make data accessible and transparent?",
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            "type": "heading",
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                    "text": "Finally, the data sources all make their data accessible and the underlying measurement transparent. They all publicly release their data, and most make it straightforward to download and use.",
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        {
            "type": "html",
            "value": "<table class=\"html-table\"><tr><td>UCDP</td><td><ul><li>Very detailed coding procedures are available and easy to access</li><li>Justifies conflict and death characteristics</li><li>Provides primary source(s) for each event</li><li>Provides context with conflict narratives</li></ul></td></tr><tr><td>Project Mars</td><td><ul><li>Very detailed coding procedures are available and easy to access</li><li>Justifies conflict and death characteristics</li></ul></td></tr><tr><td>Militarized Interstate Events</td><td><ul><li>Detailed coding procedures are available and easy to access</li><li>Justifies conflict and deaths characteristics</li><li>Provides context with conflict narratives</li></ul></td></tr><tr><td>Correlates of War \u2014 War Data</td><td><ul><li>Coding procedures are available and partially easy to access</li><li>Justifies conflict and death characteristics</li><li>Provides context with conflict narratives</li></ul></td></tr><tr><td>Correlates of War \u2014 Militarized Interstate Disputes</td><td><ul><li>Very detailed coding procedures are available and partially easy to access</li><li>Justifies conflict and deaths characteristics</li><li>Partially provides context with conflict narratives</li></ul></td></tr><tr><td>Peace Research Institute Oslo</td><td><ul><li>Detailed coding procedures are available and easy to access</li><li>Justifies conflict and death characteristics</li></ul></td></tr><tr><td>Conflict Catalog</td><td><ul><li>Coding procedures are available and easy to access</li></ul></td></tr></table>",
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            "value": [
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                    "text": "All release descriptions of how they characterize conflicts and deaths and share at least some of the coding procedures guiding the researchers.",
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                    "text": "Militarized Interstate Events and Correlates of War also provide additional helpful information by describing conflicts in accompanying reports. And UCDP shares the primary sources for each event underlying every conflict.",
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                    "url": "#note-19",
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                    "text": "There is no single \u2018best\u2019 approach to measuring armed conflicts and their deaths. All sources put a lot of effort into measuring conflicts and deaths in ways that are useful to researchers, policymakers, and interested citizens.",
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                    "text": "If you are interested in both big and smaller conflicts in recent years, in combatant and civilian deaths, or also non-state conflicts and acts of one-sided violence, UCDP is best.",
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                    "text": "If you are less interested in the most recent years and more in big and smaller conflicts that involve at least one state in the decades since World War II, PRIO data is best. If you also want the most recent years, you can use our combined UCDP+PRIO data.",
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                    "url": "#note-20",
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                    "text": "If you want to study long-term differences and changes over the last two hundred years and it is sufficient to focus on bigger conflicts, then Project Mars is best.",
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                    "text": "If you are especially interested in specific types of large conflicts over recent centuries, the Correlates of War data is best.",
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                    "text": "If, instead, you want to explore both big and small conflicts between ",
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                    "text": ", the Militarized Interstate Events data is best.",
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                    "text": "If you want to explore the source that was researchers\u2019 go-to for interstate conflicts for a long time and are fine with its less precise data, Correlates of War\u2019s Militarized Interstate Disputes data is best.",
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                    "text": "And if you want to study bigger conflicts over more than the last half millennium and are willing to accept lower data quality, the Conflict Catalog is best.",
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                    "text": "Even if you have a preferred source, it can still be useful to see what other sources show and where they agree and differ.",
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                    "text": "This means that having several approaches to measuring conflict deaths is not a flaw but a strength: it gives us different tools to understand the past, current state, and possible future of armed conflict around the world.",
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                    "text": "If you want to explore and compare the data that each dataset produces, you can do so in our work on ",
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                    "url": "https://docs.google.com/document/d/1fdECw4wt6d7_-cIeMcsBfnoUEoeKwF2Z1gj3Y8RCF4g/edit",
                    "children": [
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                            "text": "War and Peace",
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                    "text": " and in our ",
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                    "url": "https://docs.google.com/document/d/1SpyofFwtTSpD69fW6rUq-D-zM6DSsW7I7l0_bNC-AMA/edit",
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                            "text": "Conflict Data Explorers",
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                    "text": ".",
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                            "text": "I thank Edouard Mathieu, Hannah Ritchie, and Max Roser for reading drafts of this text and for very helpful comments and ideas.",
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                    "text": "Keep reading at Our World in Data",
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                                "text": "Sarkees, Meredith Reid, and Frank Wayman. 2010. ",
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                                "url": "https://archive.org/details/resorttowardatag0000sark/page/450/mode/2up",
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                                        "text": "Resort to War: A Data Guide to Inter-State, Extra-State, Intra-State, and Non-State Wars, 1816-2007",
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                                    }
                                ],
                                "spanType": "span-link"
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                                "text": ". CQ Press.",
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                                "text": "Palmer, Glenn, Roseanne McManus, Vito D\u2019Orazio, Michael Kenwick, Mikaela Karstens, Chase Bloch, Nick Dietrich, Kayla Kahn, Kellan Ritter, and Michael Soules. 2021. ",
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                                "url": "https://journals.sagepub.com/doi/full/10.1177/0738894221995743",
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                                        "text": "The MID5 Dataset, 2011-2014: Procedures, coding rules, and description",
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                                "spanType": "span-link"
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                            {
                                "text": ". Conflict Management and Peace Science 38(5): 470-482.",
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                                "text": "While UCDP and PRIO cover the same deaths and partially the same conflicts, their different sources often lead to somewhat different estimates:",
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                                "children": [
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                                        "text": "Estimating Battle Deaths: A Challenging Exercise",
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                                "text": " discusses this further.",
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                                "text": "Gibler, Douglas, and Steven Miller. 2023. ",
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                                        "text": "The Militarized Interstate Confrontation Dataset, 1816-2014",
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                                ],
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                                "text": ". Journal of Conflict Resolution. OnlineFirst.",
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                                        "text": "The Militarized Interstate Events (MIE) dataset, 1816\u20132014",
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                                "text": ". Conflict Management and Peace Science. OnlineFirst.",
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                                "text": "Davies, Shawn, Therese Pettersson, and Magnus \u00d6berg. 2023. Organized violence 1989-2022 and the return of conflicts between states? Journal of Peace Research 60(4): 691-708.",
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                                "text": ". Journal of Peace Research 39(5): 615\u2013637.",
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                                "text": "Peter Brecke, who assembled the Conflict Catalog, himself emphasizes that both the conflicts and the deaths included are incomplete, particularly for the distant past and outside of Europe.",
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                                "text": "Correlates of War labels these conflicts as intra-state if they happen within one state\u2019s territory",
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                                "text": "Richardson, Lewis Fry. 1960. Statistics of Deadly Quarrels. Boxwood Press.",
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                                        "text": "Divided Armies: Inequality and Battlefield Performance in Modern War",
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                                "text": ". Princeton University Press.",
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                                "text": "Brecke, Peter. 1999. ",
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                                        "text": "Violent Conflicts 1400 A.D. to the Present in Different Regions of the World",
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                                "spanType": "span-link"
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                                "text": ". Paper prepared for the 1999 Meeting of the Peace Science Society (International) on October 8-10, 1999 in Ann Arbor, Michigan.",
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                                "text": "Lacina, Bethany, and Nils Petter Gleditsch. 2005. ",
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                                        "text": "Monitoring Trends in Global Combat: A New Dataset of Battle Deaths",
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                                "text": ". European Journal of Population 21: 145-166.",
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                                "text": "Clodfelter, Micheal. 2017. Warfare and Armed Conflicts: A Statistical Encyclopedia of Casualty and other Figures, 1492-2015. Fourth edition. McFarland & Company.",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "parseErrors": []
                    }
                ],
                "parseErrors": []
            },
            "e38840b224955a6262fe33fefb252857f0d4bbd2": {
                "id": "e38840b224955a6262fe33fefb252857f0d4bbd2",
                "index": 10,
                "content": [
                    {
                        "type": "text",
                        "value": [
                            {
                                "text": "Sometimes, however, these terms are used interchangeably. This becomes a challenge for researchers trying to identify the specific human toll of a conflict.",
                                "spanType": "span-simple-text"
                            }
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                ],
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            },
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                "id": "e4360c786046652de9ddbd8cd5b41b0ae3731ce5",
                "index": 15,
                "content": [
                    {
                        "type": "text",
                        "value": [
                            {
                                "text": "Sorokin, Pitirim. 1937. Social and cultural dynamics. Volume Three: Fluctuation of Social Relationships, War, and Revolution. American Book Company.",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "parseErrors": []
                    }
                ],
                "parseErrors": []
            },
            "e63e18e1530df909455d816b1e898435e4e117cc": {
                "id": "e63e18e1530df909455d816b1e898435e4e117cc",
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                    {
                        "type": "text",
                        "value": [
                            {
                                "text": "This article draws on several helpful other articles summarizing and reviewing some of the datasets, as well as the datasets\u2019 codebooks and descriptions:",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "parseErrors": []
                    },
                    {
                        "type": "text",
                        "value": [
                            {
                                "text": "Brecke, Peter. 1999. ",
                                "spanType": "span-simple-text"
                            },
                            {
                                "url": "https://cpn-us-w2.wpmucdn.com/sites.gatech.edu/dist/1/19/files/2018/09/Brecke-PSS-1999-paper-Violent-Conflicts-1400-AD-to-the-Present.pdf",
                                "children": [
                                    {
                                        "text": "Violent Conflicts 1400 A.D. to the Present in Different Regions of the World",
                                        "spanType": "span-simple-text"
                                    }
                                ],
                                "spanType": "span-link"
                            },
                            {
                                "text": ". Paper prepared for the 1999 Meeting of the Peace Science Society (International) on October 8-10, 1999 in Ann Arbor, Michigan.",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "parseErrors": []
                    },
                    {
                        "type": "text",
                        "value": [
                            {
                                "text": "Brecke, Peter. 2012. ",
                                "spanType": "span-simple-text"
                            },
                            {
                                "url": "http://www.cgeh.nl/sites/default/files/Notes%20about%20Conflict%20Catalog.pdf",
                                "children": [
                                    {
                                        "text": "Notes regarding the Conflict Catalog",
                                        "spanType": "span-simple-text"
                                    }
                                ],
                                "spanType": "span-link"
                            },
                            {
                                "text": ".",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "parseErrors": []
                    },
                    {
                        "type": "text",
                        "value": [
                            {
                                "text": "Eck, Kristine, and Lisa Hultman. 2007. ",
                                "spanType": "span-simple-text"
                            },
                            {
                                "url": "https://journals.sagepub.com/doi/10.1177/0022343307075124",
                                "children": [
                                    {
                                        "text": "One-sided violence against civilians in war: insights from new fatality data",
                                        "spanType": "span-simple-text"
                                    }
                                ],
                                "spanType": "span-link"
                            },
                            {
                                "text": ". Journal of Peace Research 44(2): 233-246.",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "parseErrors": []
                    },
                    {
                        "type": "text",
                        "value": [
                            {
                                "text": "Gleditsch, Nils Petter, Peter Wallensteen, Mikael Eriksson, Margareta Sollenberg, and H\u00e5vard Strand. 2002. ",
                                "spanType": "span-simple-text"
                            },
                            {
                                "url": "https://journals.sagepub.com/doi/10.1177/0022343302039005007",
                                "children": [
                                    {
                                        "text": "Armed conflict 1946\u20132001: A new dataset",
                                        "spanType": "span-simple-text"
                                    }
                                ],
                                "spanType": "span-link"
                            },
                            {
                                "text": ". Journal of Peace Research 39(5): 615\u2013637.",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "parseErrors": []
                    },
                    {
                        "type": "text",
                        "value": [
                            {
                                "text": "Gibler, Douglas, and Steven Miller. 2022. ",
                                "spanType": "span-simple-text"
                            },
                            {
                                "url": "https://academic.oup.com/isq/article-abstract/66/2/sqac011/6569150?redirectedFrom=fulltext",
                                "children": [
                                    {
                                        "text": "An Appraisal of Project Mars and the Divided Armies Argument",
                                        "spanType": "span-simple-text"
                                    }
                                ],
                                "spanType": "span-link"
                            },
                            {
                                "text": ". International Studies Quarterly 66(2): 1-9.",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "parseErrors": []
                    },
                    {
                        "type": "text",
                        "value": [
                            {
                                "text": "Gibler, Douglas, and Steven Miller. 2023. ",
                                "spanType": "span-simple-text"
                            },
                            {
                                "url": "https://journals.sagepub.com/doi/abs/10.1177/00220027221104704",
                                "children": [
                                    {
                                        "text": "The Militarized Interstate Confrontation Dataset, 1816-2014",
                                        "spanType": "span-simple-text"
                                    }
                                ],
                                "spanType": "span-link"
                            },
                            {
                                "text": ". Journal of Conflict Resolution. OnlineFirst.",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "parseErrors": []
                    },
                    {
                        "type": "text",
                        "value": [
                            {
                                "text": "Gibler, Douglas, and Steven Miller. 2023. ",
                                "spanType": "span-simple-text"
                            },
                            {
                                "url": "https://journals.sagepub.com/doi/abs/10.1177/07388942231182674",
                                "children": [
                                    {
                                        "text": "The Militarized Interstate Events (MIE) dataset, 1816\u20132014",
                                        "spanType": "span-simple-text"
                                    }
                                ],
                                "spanType": "span-link"
                            },
                            {
                                "text": ". Conflict Management and Peace Science. OnlineFirst.",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "parseErrors": []
                    },
                    {
                        "type": "text",
                        "value": [
                            {
                                "text": "Gohdes, Anita, and Megan Price. 2012. ",
                                "spanType": "span-simple-text"
                            },
                            {
                                "url": "https://journals.sagepub.com/doi/abs/10.1177/0022002712459708",
                                "children": [
                                    {
                                        "text": "First Things First: Assessing Data Quality before Model Quality",
                                        "spanType": "span-simple-text"
                                    }
                                ],
                                "spanType": "span-link"
                            },
                            {
                                "text": ". Journal of Conflict Resolution 57(6): 1090-1108.",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "parseErrors": []
                    },
                    {
                        "type": "text",
                        "value": [
                            {
                                "text": "H\u00f6gbladh, Stina. 2022. ",
                                "spanType": "span-simple-text"
                            },
                            {
                                "url": "https://ucdp.uu.se/downloads/ged/ged221.pdf",
                                "children": [
                                    {
                                        "text": "UCDP Georeferenced Event Dataset Codebook Version 22.1",
                                        "spanType": "span-simple-text"
                                    }
                                ],
                                "spanType": "span-link"
                            },
                            {
                                "text": ".",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "parseErrors": []
                    },
                    {
                        "type": "text",
                        "value": [
                            {
                                "text": "Jones, Daniel, Stuart Bremer, and J. David Singer. 1996. ",
                                "spanType": "span-simple-text"
                            },
                            {
                                "url": "https://journals.sagepub.com/doi/10.1177/073889429601500203",
                                "children": [
                                    {
                                        "text": "Militarized Interstate Disputes, 1816-1992: Rationale, Coding Rules, and Empirical Patterns",
                                        "spanType": "span-simple-text"
                                    }
                                ],
                                "spanType": "span-link"
                            },
                            {
                                "text": ". Conflict Management and Peace Science 15(2): 163-213.",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "parseErrors": []
                    },
                    {
                        "type": "text",
                        "value": [
                            {
                                "text": "Palmer, Glenn, Roseanne McManus, Vito D\u2019Orazio, Michael Kenwick, Mikaela Karstens, Chase Bloch, Nick Dietrich, Kayla Kahn, Kellan Ritter, and Michael Soules. 2021. ",
                                "spanType": "span-simple-text"
                            },
                            {
                                "url": "https://journals.sagepub.com/doi/full/10.1177/0738894221995743",
                                "children": [
                                    {
                                        "text": "The MID5 Dataset, 2011-2014: Procedures, coding rules, and description",
                                        "spanType": "span-simple-text"
                                    }
                                ],
                                "spanType": "span-link"
                            },
                            {
                                "text": ". Conflict Management and Peace Science 38(5): 470-482.",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "parseErrors": []
                    },
                    {
                        "type": "text",
                        "value": [
                            {
                                "text": "Palmer, Glenn, Vito D\u2019Orazio, Michael Kenwick, and Matthew Lane. 2015. ",
                                "spanType": "span-simple-text"
                            },
                            {
                                "url": "https://journals.sagepub.com/doi/10.1177/0738894214559680",
                                "children": [
                                    {
                                        "text": "The MID4 dataset, 2002-2010: Procedures, coding rules and description",
                                        "spanType": "span-simple-text"
                                    }
                                ],
                                "spanType": "span-link"
                            },
                            {
                                "text": ". Conflict Management and Peace Science 32(2): 222-242.",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "parseErrors": []
                    },
                    {
                        "type": "text",
                        "value": [
                            {
                                "text": "Lacina, Bethany. 2009. ",
                                "spanType": "span-simple-text"
                            },
                            {
                                "url": "https://www.prio.org/data/1",
                                "children": [
                                    {
                                        "text": "Battle Deaths Dataset 1946\u20132008",
                                        "spanType": "span-simple-text"
                                    }
                                ],
                                "spanType": "span-link"
                            },
                            {
                                "text": ". Codebook for Version 3.0.",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "parseErrors": []
                    },
                    {
                        "type": "text",
                        "value": [
                            {
                                "text": "Lacina, Bethany, and Nils Petter Gleditsch. 2005. ",
                                "spanType": "span-simple-text"
                            },
                            {
                                "url": "https://link.springer.com/article/10.1007/s10680-005-6851-6",
                                "children": [
                                    {
                                        "text": "Monitoring Trends in Global Combat: A New Dataset of Battle Deaths",
                                        "spanType": "span-simple-text"
                                    }
                                ],
                                "spanType": "span-link"
                            },
                            {
                                "text": ". European Journal of Population 21: 145-166.",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "parseErrors": []
                    },
                    {
                        "type": "text",
                        "value": [
                            {
                                "text": "Lacina, Bethany, and Nils Petter Gledtisch. 2012. ",
                                "spanType": "span-simple-text"
                            },
                            {
                                "url": "https://journals.sagepub.com/doi/abs/10.1177/0022002712459709",
                                "children": [
                                    {
                                        "text": "The Waning of War is Real: A Response to Gohdes and Price",
                                        "spanType": "span-simple-text"
                                    }
                                ],
                                "spanType": "span-link"
                            },
                            {
                                "text": ". Journal of Conflict Resolution 57(6): 1109-1127.",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "parseErrors": []
                    },
                    {
                        "type": "text",
                        "value": [
                            {
                                "text": "Lyall, Jason. 2022. ",
                                "spanType": "span-simple-text"
                            },
                            {
                                "url": "https://dataverse.harvard.edu/dataset.xhtml?persistentId=doi:10.7910/DVN/DUO7IE",
                                "children": [
                                    {
                                        "text": "Sources, Data, Methods: The Project Mars Codebook Version 1.1",
                                        "spanType": "span-simple-text"
                                    }
                                ],
                                "spanType": "span-link"
                            },
                            {
                                "text": ".",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "parseErrors": []
                    },
                    {
                        "type": "text",
                        "value": [
                            {
                                "text": "Pettersson, Therese. 2022a. ",
                                "spanType": "span-simple-text"
                            },
                            {
                                "url": "https://ucdp.uu.se/downloads/brd/ucdp-brd-codebook-221.pdf",
                                "children": [
                                    {
                                        "text": "UCDP Battle-related Deaths Dataset Codebook v 22.1",
                                        "spanType": "span-simple-text"
                                    }
                                ],
                                "spanType": "span-link"
                            },
                            {
                                "text": ".",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "parseErrors": []
                    },
                    {
                        "type": "text",
                        "value": [
                            {
                                "text": "Pettersson, Therese. 2022b. ",
                                "spanType": "span-simple-text"
                            },
                            {
                                "url": "https://ucdp.uu.se/downloads/nsos/ucdp-nonstate-221.pdf",
                                "children": [
                                    {
                                        "text": "UCDP Non-state Conflict Codebook v 22.1",
                                        "spanType": "span-simple-text"
                                    }
                                ],
                                "spanType": "span-link"
                            },
                            {
                                "text": ".",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "parseErrors": []
                    },
                    {
                        "type": "text",
                        "value": [
                            {
                                "text": "Pettersson, Therese. 2022c. ",
                                "spanType": "span-simple-text"
                            },
                            {
                                "url": "https://ucdp.uu.se/downloads/nsos/ucdp-onesided-221.pdf",
                                "children": [
                                    {
                                        "text": "UCDP One-sided Violence Codebook v 22.1",
                                        "spanType": "span-simple-text"
                                    }
                                ],
                                "spanType": "span-link"
                            },
                            {
                                "text": ".",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "parseErrors": []
                    },
                    {
                        "type": "text",
                        "value": [
                            {
                                "text": "Sarkees, Meredith Reid, and Frank Wayman. 2010. ",
                                "spanType": "span-simple-text"
                            },
                            {
                                "url": "https://archive.org/details/resorttowardatag0000sark/page/450/mode/2up",
                                "children": [
                                    {
                                        "text": "Resort to War: A Data Guide to Inter-State, Extra-State, Intra-State, and Non-State Wars, 1816-2007",
                                        "spanType": "span-simple-text"
                                    }
                                ],
                                "spanType": "span-link"
                            },
                            {
                                "text": ". CQ Press.",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "parseErrors": []
                    },
                    {
                        "type": "text",
                        "value": [
                            {
                                "text": "Spagat, Michael, Brennen Fagan, and Stijn Van Weezel. 2022. From Gaddis to Mars: The Decline of War Enters New Territory. Working Paper.",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "parseErrors": []
                    },
                    {
                        "type": "text",
                        "value": [
                            {
                                "text": "Sundberg, Ralph, Kristine Eck, and Joakim Kreutz. 2012. ",
                                "spanType": "span-simple-text"
                            },
                            {
                                "url": "https://journals.sagepub.com/doi/abs/10.1177/0022343311431598",
                                "children": [
                                    {
                                        "text": "Introducing the UCDP Non-State Conflict Dataset",
                                        "spanType": "span-simple-text"
                                    }
                                ],
                                "spanType": "span-link"
                            },
                            {
                                "text": ". Journal of Peace Research 49(2): 351-362.",
                                "spanType": "span-simple-text"
                            }
                        ],
                        "parseErrors": []
                    }
                ],
                "parseErrors": []
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                "index": 18,
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                    {
                        "type": "text",
                        "value": [
                            {
                                "text": "Militarized Interstate Events has plans to share the source(s) for each of its events.",
                                "spanType": "span-simple-text"
                            }
                        ],
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    },
    "type": "article",
    "title": "How major sources collect data on conflicts and conflict deaths, and when to use which one",
    "authors": [
        "Bastian Herre"
    ],
    "excerpt": "There are many ways to measure armed conflicts and conflict deaths. What approaches do different researchers take? And when is which approach best?",
    "subtitle": "There are many ways to measure armed conflicts and conflict deaths. What approaches do different researchers take? And when is which approach best?",
    "featured-image": "conflict-data-how-do-researchers-measure-armed-conflicts-and-their-deaths.png"
}

2023-06-29 15:51:04

2023-10-13 16:03:57

2024-02-16 17:38:25

listed

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<Callout title="More on conflict data"/> Measuring armed conflicts and conflict deaths across the world helps us understand how people’s lives and livelihoods are affected by large-scale violence. But this comes with many challenges. People do not always agree on what characteristics define an armed conflict. Even once defined, these characteristics — especially how many people died in them — are difficult to assess. The people affected are not always asked who has died around them due to the conflict. The conflict parties may underreport deaths to claim success, or overreport them to encourage intervention by third parties. Independent observers may also struggle to be present in all places and document a conflict’s death toll. So how do researchers address these challenges? In our work on [War and Peace](https://ourworldindata.org/war-and-peace), we provide data from six sources that identify armed conflicts and count their deaths: * Uppsala Conflict Data Program (UCDP)1 * Project Mars by Jason Lyall (2022)2 * Militarized Interstate Events by Douglas Gibler and Steven Miller3 * Correlates of War (CoW)4 * Peace Research Institute Oslo (PRIO)5 * Conflict Catalog by Peter Brecke (1999)6 These sources all measure armed conflicts and their deaths; they cover many countries and years, and researchers and policymakers frequently use them. In our [Conflict Data Explorers](https://docs.google.com/document/d/1SpyofFwtTSpD69fW6rUq-D-zM6DSsW7I7l0_bNC-AMA/edit), you can delve into global and regional overviews of conflicts and their deaths. Reassuringly, sources typically agree about big differences in the deaths from armed conflicts: they readily distinguish between deadly and peaceful years. But they do not always agree. They often come to different assessments about _how _widespread and deadly some years were. Why do these sources arrive at different numbers? And is there any best approach? I summarize the key similarities and differences between the different approaches in this article and when to use which one. # What conflicts are covered? In this table and the ones that follow, I summarize what armed conflicts and conflict deaths each data source covers.7 <table class="html-table"><tr><td>UCDP</td><td><ul><li>Armed conflicts: interstate, intrastate, extrastate, non-state, and one-sided violence</li><li>At least 25 deaths during a year (based on most plausible estimate)<a class="ref" href="#note-8"><sup>8</sup></a></li></ul></td></tr><tr><td>Project Mars</td><td><ul><li>Conventional wars: interstate; de facto also intrastate and extrastate</li><li>At least 500 deaths (based on highest plausible estimate)</li><li>Primary combatants have differentiated militaries, and clear frontlines</li></ul></td></tr><tr><td>Militarized Interstate Events</td><td><ul><li>Militarized interstate confrontations: interstate threats of force, display of force, use of force, war</li></ul></td></tr><tr><td>Correlates of War — Wars</td><td><ul><li>Wars: interstate, intrastate, extrastate, and non-state</li><li>At least 1,000 deaths during a year</li></ul></td></tr><tr><td>Correlates of War — Militarized Interstate Disputes</td><td><ul><li>Militarized interstate disputes: interstate threats of force, display of force, use of force, war</li><li>At least use of force threatened</li><li>At least 1,000 deaths during a year for war</li></ul></td></tr><tr><td>Peace Research Institute Oslo</td><td><ul><li>Armed conflicts: interstate, intrastate, and extrastate</li><li>At least 25 deaths during a year</li></ul></td></tr><tr><td>Conflict Catalog</td><td><ul><li>Violent political conflicts: interstate, intrastate, extrastate, non-state and one-sided violence</li><li>At least 32 deaths during a year</li></ul></td></tr></table> All sources characterize an armed conflict as a disagreement between organized groups that involves force. For most datasets, this means that force is used. But for the Militarized Interstate Events data and Correlates of War’s Militarized Interstate Disputes data, this can also mean that force is threatened or displayed. Approaches also differ in what types of conflicts they cover and how many deaths they must cause to be included. They all include armed conflicts where the primary combatants are states (interstate conflicts), and most cover those conflicts between a state and an armed group that is not a state inside the state’s territory (intrastate conflicts) or outside the state’s territory (extrastate conflicts).9 These conflicts are sometimes grouped together as “state-based” conflicts. Some approaches go further and also include conflicts where neither armed group is a state (non-state conflicts). 10 And some even include violence by an armed group — state or non-state — against civilians (one-sided violence). Most sources only include conflicts if they cause many deaths. Some set a threshold of at least 500 or 1,000 annual or total deaths, and then call these deadly conflicts _wars_. Others include more minor armed conflicts that cause a few dozen deaths during a year. And the Militarized Interstate Events data and Correlates of War’s Militarized Interstate Disputes data also include conflicts in which no one died. Finally, the specific definitions of the sources mean that their conflicts differ slightly beyond their differences in conflict type and death toll. The biggest of these minor differences is that Project Mars only includes conventional wars, those fought between differentiated militaries along clear frontlines. Others do not make such a distinction. # Which deaths are included? The data sources also differ in who they include in their death counts and how they were killed. <table class="html-table"><tr><td>UCDP</td><td><ul><li>Total, combatant, and civilian deaths, due to fighting</li></ul></td></tr><tr><td>Project Mars</td><td><ul><li>Deaths of combatants, due to fighting</li></ul></td></tr><tr><td>Militarized Interstate Events</td><td><ul><li>Deaths of combatants, due to fighting</li></ul></td></tr><tr><td>Correlates of War — War Data</td><td><ul><li>Deaths of combatants, due to fighting, disease, and starvation</li></ul></td></tr><tr><td>Correlates of War — Militarized Interstate Disputes</td><td><ul><li>Deaths of combatants, due to fighting</li></ul></td></tr><tr><td>Peace Research Institute Oslo</td><td><ul><li>Deaths of combatants and civilians, due to fighting</li></ul></td></tr><tr><td>Conflict Catalog</td><td><ul><li>Total, combatant, and civilian deaths, due to fighting, disease, and starvation</li></ul></td></tr></table> All sources record deaths, the people killed in the conflict. This is different from other sources which record casualties, which include both deaths and those wounded. Yet other sources even tally losses, including both casualties and those deserted.11 But some approaches only include deaths of combatants — those doing the fighting. Others also include civilians — those who do not take up any weapons but may be killed accidentally or intentionally (in cases of one-sided violence). These civilian deaths also include victims of terrorist attacks, as long as the attack was carried out by an armed group.12 And some approaches only include direct, or battle-related, deaths — those due to the fighting. Meanwhile, others include direct and indirect, or war-related, deaths — both those due to fighting, and those due to disease or starvation caused by the conflict. # What years and countries are covered? All data sources provide historical data and cover conflicts worldwide. But they differ in what years they cover, and which countries and regions they consider sovereign states. <table class="html-table"><tr><td>UCDP</td><td><ul><li>1989 — ongoing</li><li>Global</li></ul></td></tr><tr><td>Project Mars</td><td><ul><li>1800 — 2011 / ongoing</li><li>Global</li></ul></td></tr><tr><td>Militarized Interstate Events</td><td><ul><li>1816 — 2014 / ongoing</li><li>Global</li></ul></td></tr><tr><td>Correlates of War — War Data</td><td><ul><li>1816 — 2007 (extrastate, non-state), 1816 — 2010 (inter-state), 1816 — 2014 (intrastate) / ongoing</li><li>Global</li></ul></td></tr><tr><td>Correlates of War — Militarized Interstate Disputes</td><td><ul><li>1816 — 2014 / ongoing</li><li>Global</li></ul></td></tr><tr><td>Peace Research Institute Oslo</td><td><ul><li>1946 — 2008</li><li>Global</li></ul></td></tr><tr><td>Conflict Catalog</td><td><ul><li>1400 — 2000</li><li>Global</li></ul></td></tr></table> UCDP currently provides the most recent data, as it is updated each year. Other sources are updated less frequently and currently have a delay of about a decade on their most recent data (Project Mars, Militarized Interstate Events, and Correlates of War), or they are no longer maintained and will likely not be updated for recent decades (Conflict Catalog and PRIO). In turn, UCDP only begins at the end of the Cold War. In contrast, the other sources start in the mid- or early 20th century (PRIO), the early 19th century (Project Mars, Militarized Interstate Events, and Correlates of War), or even reach as far back in time as the year 1400 (Conflict Catalog). The data sources also differ in which countries and regions they consider sovereign states. Correlates of War and Militarized Interstate Events use the state system by [Correlates of War](https://ourworldindata.org/grapher/sovereign-state-cow), which until 1919 requires diplomatic recognition by France and the United Kingdom for a country to be included. UCDP and PRIO meanwhile use the slightly more inclusive list of sovereign states by [Gleditsch and Ward](https://ourworldindata.org/grapher/sovereign-state-gleditsch-ward). Project Mars and the Conflict Catalog have even more expansive definitions of statehood, and are closer to the state system as identified by [Butcher and Griffiths](https://ourworldindata.org/grapher/sovereign-state-butcher-griffiths). This affects how some conflicts are classified, as an extrastate or non-state war in Correlates of War’s war data can be classified as an interstate or civil war in Project Mars. And it affects how conflict rates are [calculated](https://docs.google.com/document/d/1H_dmh_1YYoY605lcVHtyOm2RZ2AfpIUuimG99ubmcHs/edit), as the number of countries for each year can [differ a lot](https://ourworldindata.org/grapher/number-of-countries), [especially](https://ourworldindata.org/grapher/number-of-countries-by-region) for Africa and Asia and Oceania. # How are conflicts and deaths identified? Generally, the data sources are similar in how they go about assessing conflicts and the deaths in them. <table class="html-table"><tr><td>UCDP</td><td><ul><li>Evaluations by own researchers of news reports, other contemporary sources, and academic research</li></ul></td></tr><tr><td>Project Mars</td><td><ul><li>Evaluations by own researchers of academic research (including UCDP and CoW), news reports, and other contemporary sources</li></ul></td></tr><tr><td>Militarized Interstate Events</td><td><ul><li>Evaluations by own researchers of academic research (including CoW) and news reports, other contemporary sources, and academic research</li></ul></td></tr><tr><td>Correlates of War — War Data</td><td><ul><li>Evaluations by own researchers of academic research</li></ul></td></tr><tr><td>Correlates of War — Militarized Interstate Disputes</td><td><ul><li>Evaluations by own researchers of academic research and news reports filtered by machine learning</li></ul></td></tr><tr><td>Peace Research Institute Oslo</td><td><ul><li>Evaluations by own researchers of academic research (including UCDP), official death statistics, surveys, news reports, and other archival sources<a class="ref" href="#note-13"><sup>13</sup></a></li></ul></td></tr><tr><td>Conflict Catalog</td><td><ul><li>Own evaluations of academic research (including CoW) and other sources</li></ul></td></tr></table> All rely on researchers evaluating independent news reports, academic research, or both. Some also supplement these primary sources with available surveys of the affected populations, or official death statistics. The primary sources they use can partially overlap. Some use the same sources, such as the encyclopedias by Micheal Clodfelter14 Lewis Fry Richardson15, and Pitirim Sorokin16. Or they outright rely on each other as the sources: PRIO and Project Mars use UCDP data, and Project Mars, Militarized Interstate Events, and the Conflict Catalog build on Correlates of War.17 # How do sources work to measure what they want to measure? The next tables summarize how the data sources address the specific challenges of measuring armed conflicts and conflict deaths. The first challenge is to make their assessments valid — to actually measure what they want to measure. <table class="html-table"><tr><td>UCDP</td><td><ul><li>Own researchers know measurement procedures and conflicts well</li><li>Include civilian deaths, as difference to combatants can be blurry</li><li>Exclude deaths due to disease and starvation as well as wounded, as difficult to identify</li></ul></td></tr><tr><td>Project Mars</td><td><ul><li>Own researchers know measurement procedures well</li><li>Exclude civilian deaths, deaths due to disease and starvation, as well as wounded, as interested in military lethality on the battlefield</li></ul></td></tr><tr><td>Militarized Interstate Events</td><td><ul><li>Own researchers know measurement procedures well</li><li>Investigate closely country-pairs with high predicted likelihood of conflict</li></ul></td></tr><tr><td>Correlates of War — War Data</td><td><ul><li>Own researchers know measurement procedures well</li><li>Include deaths due to disease and starvation, as they are integral to war, and often not distinguished from fighting in sources</li><li>Exclude civilian deaths, as difficult to identify</li><li>Sometimes estimate deaths if only number of casualties available</li></ul></td></tr><tr><td>Correlates of War — Militarized Interstate Disputes</td><td><ul><li>Own researchers know measurement procedures well</li><li>Machine learning can process vast numbers of news reports</li><li>Group deaths into broad ranges because number of deaths often uncertain</li></ul></td></tr><tr><td>Peace Research Institute Oslo</td><td><ul><li>Own researchers know measurement procedures well</li><li>Include civilian deaths, as difference to combatants can be blurry</li><li>Exclude deaths due to disease and starvation, as difficult to identify</li></ul></td></tr><tr><td>Conflict Catalog</td><td><ul><li>Own researchers know measurement procedures well</li></ul></td></tr></table> In general, the sources relying on their own researchers have the advantage that these researchers know the respective definitions of armed conflicts and related deaths well and are very familiar with the measurement procedures, which makes it more likely that they code as intended. However, the sources differ in the deaths they include because they weigh the challenges of measurement differently. Some include civilian deaths because they often find it too difficult to distinguish them from combatant deaths. Others exclude them because they find them too difficult to identify comprehensively or because they are only interested in the actions of militaries on the battlefield. Some approaches include deaths due to disease and starvation because they consider them a fundamental part of war, and because primary sources often do not distinguish between them and deaths due to fighting. But others do not, as they find such indirect deaths too challenging to identify comprehensively. Finally, Correlates of War’s war data sometimes estimates the number of deaths based on the number of conflict casualties, if only those are available. And its Militarized Interstate Disputes data mostly groups deaths into broad ranges, as it finds determining more specific numbers too uncertain. # How do sources work to make assessments precise? The sources are also concerned with making their assessments precise and reliable. <table class="html-table"><tr><td>UCDP</td><td><ul><li>Many and different types of sources used</li><li>Not covering earlier years</li><li>Conflicts disaggregated into years and individual events (with at least one death per event)</li><li>Report types of deaths separately</li></ul></td></tr><tr><td>Project Mars</td><td><ul><li>More than 100 researchers split into adversarial teams search at least 10 quality sources per deaths estimate</li><li>Not covering earlier years</li><li>Big and recurrent wars disaggregated into campaigns</li></ul></td></tr><tr><td>Militarized Interstate Events</td><td><ul><li>Many and different types of primary sources used</li><li>Not covering earlier years</li><li>Conflicts disaggregated into years and individual events</li></ul></td></tr><tr><td>Correlates of War — War Data</td><td><ul><li>Many and different types of primary sources used</li><li>Not covering earlier years</li></ul></td></tr><tr><td>Correlates of War — Militarized Interstate Disputes</td><td><ul><li>Many and different types of primary sources used</li><li>Not covering earlier years</li><li>Conflicts partially disaggregated into individual incidents</li></ul></td></tr><tr><td>Peace Research Institute Oslo</td><td><ul><li>Many and different types of sources used</li><li>Not covering earlier years</li><li>Conflicts disaggregated into years</li></ul></td></tr><tr><td>Conflict Catalog</td><td><ul><li>Many and different types of primary sources used</li><li>Not covering earlier years</li><li>Big conflicts disaggregated into smaller ones</li><li>Report types of deaths separately</li></ul></td></tr></table> They all use many primary sources, and most use different types of sources, such as news reports, academic books and articles, or NGO documents. They also all avoid covering conflicts that happened even earlier — even though they differ in how far they think they can go back in time and still have data that is sufficiently reliable: UCDP begins in 1989, whereas the Conflict Catalog starts in the year 1400.18 Several sources also disaggregate their data to make it more precise: they split their estimates of deaths into total, combatant, and civilian deaths, when possible; disaggregate bigger conflicts into smaller ones; or each conflict into years, campaigns, or even specific events. # How do sources work to make assessments comparable? The sources also face the challenge of making the data comparable across conflicts and time. <table class="html-table"><tr><td>UCDP</td><td><ul><li>Researchers have very precise definitions of conflict, deaths, and other event characteristics</li><li>Global news used first, then (sometimes translated) local and specialized sources</li></ul></td></tr><tr><td>Project Mars</td><td><ul><li>Researchers have very precise definitions of conflict and deaths</li><li>Primary sources in 21 languages used</li></ul></td></tr><tr><td>Militarized Interstate Events</td><td><ul><li>Exclude civilian deaths, as they have become more common</li><li>Global news used because more comprehensive</li></ul></td></tr><tr><td>Correlates of War — War Data</td><td><ul><li>Exclude civilian deaths, as they have become more common</li></ul></td></tr><tr><td>Correlates of War — Militarized Interstate Disputes</td><td><ul><li>Exclude civilian deaths, as they have become more common</li><li>Global news used because more comprehensive</li></ul></td></tr><tr><td>Peace Research Institute Oslo</td><td><ul><li>Researchers have precise definitions of conflict and deaths</li></ul></td></tr><tr><td>Conflict Catalog</td><td><ul><li>Also non-English sources used</li></ul></td></tr></table> Some do so by providing their researchers with precise definitions of conflicts and deaths, making it easier to decide which to include. And some also use primary sources in different languages or first identify conflicts and deaths with global sources and then use more local ones. Others, meanwhile, prefer global sources for their more comprehensive coverage of international affairs. # How are the remaining differences between primary sources dealt with? The sources work to address any remaining differences between primary sources, even if they do so differently. <table class="html-table"><tr><td>UCDP</td><td><ul><li>Consider quality of primary sources, discuss within team, use most reliable one</li><li>Provide best, low, and high deaths estimates provided if several plausible</li><li>Use lower as the best estimate if no primary source is more reliable than others; best estimate therefore likely no overcount</li></ul></td></tr><tr><td>Project Mars</td><td><ul><li>Consider quality of primary sources, discuss among coder teams</li><li>Provide low and high estimates</li></ul></td></tr><tr><td>Militarized Interstate Events</td><td><ul><li>Consider quality of primary sources, discuss among coders</li><li>Provide low and high estimates</li></ul></td></tr><tr><td>Correlates of War — War Data</td><td><ul><li>Consider quality of primary sources and context (army size, weapons, medical technology, etc.)</li></ul></td></tr><tr><td>Correlates of War — Militarized Interstate Disputes</td><td><ul><li>Consider quality of primary sources, discuss among coders</li><li>Provide low and high estimates</li><li>Include accusations by targeted state even if denied by allegedly targeting state</li></ul></td></tr><tr><td>Peace Research Institute Oslo</td><td><ul><li>Consider quality of primary sources, use most reliable one</li><li>Provide best, low, and high deaths estimates</li></ul></td></tr><tr><td>Conflict Catalog</td><td><ul><li>Consider quality of primary sources</li></ul></td></tr></table> They all consider the quality of primary sources and prefer more reliable ones. Some also consider the context of the conflicts — such as army size and weapons used — to assess which accounts are more plausible. Others also discuss any discrepancies between researchers on their team. This adds an additional step to make the assessments comparable across coders, conflicts, and time. Correlates of War’s Militarized Interstate Disputes data partially reconciles differences between conflict parties by erring on the side of including accusations by a targeted state even if the state allegedly targeting it denies them. Several approaches provide more than one estimate of conflict deaths and share a low, high, and sometimes also a best estimate. By doing so, they avoid forcing themselves to eliminate all uncertainty and possibly biasing their estimates. UCDP combines these strategies and uses the lower estimate as the best one if no primary source is more reliable than others. It thereby reduces the risk that the estimate overcounts deaths. # How do sources work to make data accessible and transparent? Finally, the data sources all make their data accessible and the underlying measurement transparent. They all publicly release their data, and most make it straightforward to download and use. <table class="html-table"><tr><td>UCDP</td><td><ul><li>Very detailed coding procedures are available and easy to access</li><li>Justifies conflict and death characteristics</li><li>Provides primary source(s) for each event</li><li>Provides context with conflict narratives</li></ul></td></tr><tr><td>Project Mars</td><td><ul><li>Very detailed coding procedures are available and easy to access</li><li>Justifies conflict and death characteristics</li></ul></td></tr><tr><td>Militarized Interstate Events</td><td><ul><li>Detailed coding procedures are available and easy to access</li><li>Justifies conflict and deaths characteristics</li><li>Provides context with conflict narratives</li></ul></td></tr><tr><td>Correlates of War — War Data</td><td><ul><li>Coding procedures are available and partially easy to access</li><li>Justifies conflict and death characteristics</li><li>Provides context with conflict narratives</li></ul></td></tr><tr><td>Correlates of War — Militarized Interstate Disputes</td><td><ul><li>Very detailed coding procedures are available and partially easy to access</li><li>Justifies conflict and deaths characteristics</li><li>Partially provides context with conflict narratives</li></ul></td></tr><tr><td>Peace Research Institute Oslo</td><td><ul><li>Detailed coding procedures are available and easy to access</li><li>Justifies conflict and death characteristics</li></ul></td></tr><tr><td>Conflict Catalog</td><td><ul><li>Coding procedures are available and easy to access</li></ul></td></tr></table> All release descriptions of how they characterize conflicts and deaths and share at least some of the coding procedures guiding the researchers. Militarized Interstate Events and Correlates of War also provide additional helpful information by describing conflicts in accompanying reports. And UCDP shares the primary sources for each event underlying every conflict.19 # The best source depends on your questions There is no single ‘best’ approach to measuring armed conflicts and their deaths. All sources put a lot of effort into measuring conflicts and deaths in ways that are useful to researchers, policymakers, and interested citizens. The most appropriate source depends on what questions you want to answer. It is the one that captures the conflicts, deaths, and time you are interested in. If you are interested in both big and smaller conflicts in recent years, in combatant and civilian deaths, or also non-state conflicts and acts of one-sided violence, UCDP is best. If you are less interested in the most recent years and more in big and smaller conflicts that involve at least one state in the decades since World War II, PRIO data is best. If you also want the most recent years, you can use our combined UCDP+PRIO data.20 If you want to study long-term differences and changes over the last two hundred years and it is sufficient to focus on bigger conflicts, then Project Mars is best. If you are especially interested in specific types of large conflicts over recent centuries, the Correlates of War data is best. If, instead, you want to explore both big and small conflicts between _states_, the Militarized Interstate Events data is best. If you want to explore the source that was researchers’ go-to for interstate conflicts for a long time and are fine with its less precise data, Correlates of War’s Militarized Interstate Disputes data is best. And if you want to study bigger conflicts over more than the last half millennium and are willing to accept lower data quality, the Conflict Catalog is best. This means that having several approaches to measuring conflict deaths is not a flaw but a strength: it gives us different tools to understand the past, current state, and possible future of armed conflict around the world. If you want to explore and compare the data that each dataset produces, you can do so in our work on [War and Peace](https://docs.google.com/document/d/1fdECw4wt6d7_-cIeMcsBfnoUEoeKwF2Z1gj3Y8RCF4g/edit) and in our [Conflict Data Explorers](https://docs.google.com/document/d/1SpyofFwtTSpD69fW6rUq-D-zM6DSsW7I7l0_bNC-AMA/edit). <Callout title="Acknowledgements"/> ## Keep reading at Our World in Data ### undefined undefined https://docs.google.com/document/d/1H_dmh_1YYoY605lcVHtyOm2RZ2AfpIUuimG99ubmcHs/edit ### undefined undefined https://docs.google.com/document/d/1SpyofFwtTSpD69fW6rUq-D-zM6DSsW7I7l0_bNC-AMA/edit Davies, Shawn, Therese Pettersson, and Magnus Öberg. 2023. Organized violence 1989-2022 and the return of conflicts between states? Journal of Peace Research 60(4): 691-708. Gleditsch, Nils Petter, Peter Wallensteen, Mikael Eriksson, Margareta Sollenberg, and Håvard Strand. 2002. [Armed conflict 1946–2001: A new dataset](https://journals.sagepub.com/doi/10.1177/0022343302039005007). Journal of Peace Research 39(5): 615–637. Gibler, Douglas, and Steven Miller. 2023. [The Militarized Interstate Confrontation Dataset, 1816-2014](https://journals.sagepub.com/doi/abs/10.1177/00220027221104704). Journal of Conflict Resolution. OnlineFirst. Gibler, Douglas, and Steven Miller. 2023. [The Militarized Interstate Events (MIE) dataset, 1816–2014](https://journals.sagepub.com/doi/abs/10.1177/07388942231182674). Conflict Management and Peace Science. OnlineFirst. Sarkees, Meredith Reid, and Frank Wayman. 2010. [Resort to War: A Data Guide to Inter-State, Extra-State, Intra-State, and Non-State Wars, 1816-2007](https://archive.org/details/resorttowardatag0000sark/page/450/mode/2up). CQ Press. Palmer, Glenn, Roseanne McManus, Vito D’Orazio, Michael Kenwick, Mikaela Karstens, Chase Bloch, Nick Dietrich, Kayla Kahn, Kellan Ritter, and Michael Soules. 2021. [The MID5 Dataset, 2011-2014: Procedures, coding rules, and description](https://journals.sagepub.com/doi/full/10.1177/0738894221995743). Conflict Management and Peace Science 38(5): 470-482. While UCDP and PRIO cover the same deaths and partially the same conflicts, their different sources often lead to somewhat different estimates: UCDP collects data on deaths for each individual conflict event, whereas PRIO uses less specific summary estimates. UCDP also looks at non-state conflicts and one-sided violence, which PRIO does not. Yet, PRIO’s summary estimates may still partially include deaths from non-state conflicts or one-sided violence that are closely tied to the state-based conflicts it covers. UCDP only includes an event if it can identify the perpetrator. Because PRIO does not look at events, its summary estimates may partially include deaths where a likely perpetrator was identified as likely, but not conclusively determined. These differences explain why UCDP tends to report fewer deaths than PRIO. The joint UCDP and PRIO report [Estimating Battle Deaths: A Challenging Exercise](https://www.pcr.uu.se/digitalAssets/666/c_666984-l_1-k_hsrp_est.battle_deaths_1.2.13.pdf) discusses this further. Lyall, Jason. 2020. [Divided Armies: Inequality and Battlefield Performance in Modern War](https://press.princeton.edu/books/paperback/9780691192444/divided-armies). Princeton University Press. Lacina, Bethany, and Nils Petter Gleditsch. 2005. [Monitoring Trends in Global Combat: A New Dataset of Battle Deaths](https://link.springer.com/article/10.1007/s10680-005-6851-6). European Journal of Population 21: 145-166. Brecke, Peter. 1999. [Violent Conflicts 1400 A.D. to the Present in Different Regions of the World](https://cpn-us-w2.wpmucdn.com/sites.gatech.edu/dist/1/19/files/2018/09/Brecke-PSS-1999-paper-Violent-Conflicts-1400-AD-to-the-Present.pdf). Paper prepared for the 1999 Meeting of the Peace Science Society (International) on October 8-10, 1999 in Ann Arbor, Michigan. This article draws on several helpful other articles summarizing and reviewing some of the datasets, as well as the datasets’ codebooks and descriptions: Brecke, Peter. 1999. [Violent Conflicts 1400 A.D. to the Present in Different Regions of the World](https://cpn-us-w2.wpmucdn.com/sites.gatech.edu/dist/1/19/files/2018/09/Brecke-PSS-1999-paper-Violent-Conflicts-1400-AD-to-the-Present.pdf). Paper prepared for the 1999 Meeting of the Peace Science Society (International) on October 8-10, 1999 in Ann Arbor, Michigan. Brecke, Peter. 2012. [Notes regarding the Conflict Catalog](http://www.cgeh.nl/sites/default/files/Notes%20about%20Conflict%20Catalog.pdf). Eck, Kristine, and Lisa Hultman. 2007. [One-sided violence against civilians in war: insights from new fatality data](https://journals.sagepub.com/doi/10.1177/0022343307075124). Journal of Peace Research 44(2): 233-246. Gleditsch, Nils Petter, Peter Wallensteen, Mikael Eriksson, Margareta Sollenberg, and Håvard Strand. 2002. [Armed conflict 1946–2001: A new dataset](https://journals.sagepub.com/doi/10.1177/0022343302039005007). Journal of Peace Research 39(5): 615–637. Gibler, Douglas, and Steven Miller. 2022. [An Appraisal of Project Mars and the Divided Armies Argument](https://academic.oup.com/isq/article-abstract/66/2/sqac011/6569150?redirectedFrom=fulltext). International Studies Quarterly 66(2): 1-9. Gibler, Douglas, and Steven Miller. 2023. [The Militarized Interstate Confrontation Dataset, 1816-2014](https://journals.sagepub.com/doi/abs/10.1177/00220027221104704). Journal of Conflict Resolution. OnlineFirst. Gibler, Douglas, and Steven Miller. 2023. [The Militarized Interstate Events (MIE) dataset, 1816–2014](https://journals.sagepub.com/doi/abs/10.1177/07388942231182674). Conflict Management and Peace Science. OnlineFirst. Gohdes, Anita, and Megan Price. 2012. [First Things First: Assessing Data Quality before Model Quality](https://journals.sagepub.com/doi/abs/10.1177/0022002712459708). Journal of Conflict Resolution 57(6): 1090-1108. Högbladh, Stina. 2022. [UCDP Georeferenced Event Dataset Codebook Version 22.1](https://ucdp.uu.se/downloads/ged/ged221.pdf). Jones, Daniel, Stuart Bremer, and J. David Singer. 1996. [Militarized Interstate Disputes, 1816-1992: Rationale, Coding Rules, and Empirical Patterns](https://journals.sagepub.com/doi/10.1177/073889429601500203). Conflict Management and Peace Science 15(2): 163-213. Palmer, Glenn, Roseanne McManus, Vito D’Orazio, Michael Kenwick, Mikaela Karstens, Chase Bloch, Nick Dietrich, Kayla Kahn, Kellan Ritter, and Michael Soules. 2021. [The MID5 Dataset, 2011-2014: Procedures, coding rules, and description](https://journals.sagepub.com/doi/full/10.1177/0738894221995743). Conflict Management and Peace Science 38(5): 470-482. Palmer, Glenn, Vito D’Orazio, Michael Kenwick, and Matthew Lane. 2015. [The MID4 dataset, 2002-2010: Procedures, coding rules and description](https://journals.sagepub.com/doi/10.1177/0738894214559680). Conflict Management and Peace Science 32(2): 222-242. Lacina, Bethany. 2009. [Battle Deaths Dataset 1946–2008](https://www.prio.org/data/1). Codebook for Version 3.0. Lacina, Bethany, and Nils Petter Gleditsch. 2005. [Monitoring Trends in Global Combat: A New Dataset of Battle Deaths](https://link.springer.com/article/10.1007/s10680-005-6851-6). European Journal of Population 21: 145-166. Lacina, Bethany, and Nils Petter Gledtisch. 2012. [The Waning of War is Real: A Response to Gohdes and Price](https://journals.sagepub.com/doi/abs/10.1177/0022002712459709). Journal of Conflict Resolution 57(6): 1109-1127. Lyall, Jason. 2022. [Sources, Data, Methods: The Project Mars Codebook Version 1.1](https://dataverse.harvard.edu/dataset.xhtml?persistentId=doi:10.7910/DVN/DUO7IE). Pettersson, Therese. 2022a. [UCDP Battle-related Deaths Dataset Codebook v 22.1](https://ucdp.uu.se/downloads/brd/ucdp-brd-codebook-221.pdf). Pettersson, Therese. 2022b. [UCDP Non-state Conflict Codebook v 22.1](https://ucdp.uu.se/downloads/nsos/ucdp-nonstate-221.pdf). Pettersson, Therese. 2022c. [UCDP One-sided Violence Codebook v 22.1](https://ucdp.uu.se/downloads/nsos/ucdp-onesided-221.pdf). Sarkees, Meredith Reid, and Frank Wayman. 2010. [Resort to War: A Data Guide to Inter-State, Extra-State, Intra-State, and Non-State Wars, 1816-2007](https://archive.org/details/resorttowardatag0000sark/page/450/mode/2up). CQ Press. Spagat, Michael, Brennen Fagan, and Stijn Van Weezel. 2022. From Gaddis to Mars: The Decline of War Enters New Territory. Working Paper. Sundberg, Ralph, Kristine Eck, and Joakim Kreutz. 2012. [Introducing the UCDP Non-State Conflict Dataset](https://journals.sagepub.com/doi/abs/10.1177/0022343311431598). Journal of Peace Research 49(2): 351-362. UCDP also includes a conflict with fewer than 25 deaths in a year when it has passed this threshold at least once. But they consider such a conflict to be inactive. Project Mars formally only includes interstate conflicts, but de facto includes intrastate and extrastate conflicts because it has a broader definition of what armed groups are considered states: conflicts in which combatants are fighting over governing a state they both claim authority over can still be included. Correlates of War labels these conflicts as intra-state if they happen within one state’s territory Sometimes, however, these terms are used interchangeably. This becomes a challenge for researchers trying to identify the specific human toll of a conflict. We discuss how deaths from terrorism are identified in [our article](https://docs.google.com/document/d/1ADv-Q76wuEHYOuCCf4oI-pqU4rBM7FXo_kMGR267tm0/edit) on the Global Terrorism Database. Clodfelter, Micheal. 2017. Warfare and Armed Conflicts: A Statistical Encyclopedia of Casualty and other Figures, 1492-2015. Fourth edition. McFarland & Company. Richardson, Lewis Fry. 1960. Statistics of Deadly Quarrels. Boxwood Press. Sorokin, Pitirim. 1937. Social and cultural dynamics. Volume Three: Fluctuation of Social Relationships, War, and Revolution. American Book Company. The Institute for Health Metrics and Evaluation’s Global Burden of Disease also partially relies on UCDP to calculate its estimates of [deaths from conflict and terrorism](https://ourworldindata.org/grapher/death-rates-from-conflict-and-terrorism-gbd?country=~AFG). Peter Brecke, who assembled the Conflict Catalog, himself emphasizes that both the conflicts and the deaths included are incomplete, particularly for the distant past and outside of Europe. Militarized Interstate Events has plans to share the source(s) for each of its events. For example, here are [deaths in state-based conflicts by region](https://ourworldindata.org/grapher/deaths-in-state-based-conflicts-by-region) and [deaths in state-based conflict by conflict type](https://ourworldindata.org/grapher/deaths-in-state-based-conflicts-by-type).

How major sources collect data on conflicts and conflict deaths, and when to use which one

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