Project Description

The Issue Correlates of War (ICOW) project is a research project that is collecting systematic data on contentious issues in world politics. The project was honored with the 2019 J. David Singer Data Innovation Award from the American Political Science Association's Conflict Processes section, which is "given for the best data contribution to the study of any and all forms of political conflict, either within or between nation-states."

More detail on the project's goals and theoretical underpinnings may be found in the papers generated by the project, particularly the following:

The project was started in 1997 by Paul R. Hensel, then at the Political Science department at Florida State University and now at the University of North Texas. The project began with a focus on territorial claims, which had the greatest amount of scholarly interest at the time, but with the intention of expanding to other issue types in the future (which is why it was called the Issue Correlates of War project, not something like the Territorial Correlates of War project). Sara McLaughlin Mitchell, then also at Florida State University and now at the University of Iowa, joined the project several years later as co-director, and the project expanded to include river claims and maritime claims. Krista Wiegand of the University of Tennessee and Andy Owsiak of the University of Georgia joined the project in 2015 for the creation of the identity claims data set. Beyond these principal investigators, dozens of research assistants have worked on ICOW data sets (listed in alphabetical order on the respective web pages for each ICOW data set). Some served as research assistant for a single semester or for a few summer research hours, while others -- most notably Mike Allison, Marit Brochmann, Bryan Frederick, Chris Macaulay, Tom Sowers, and John Tures -- spent substantial amounts of time working for the project over several years.

The Project's Name

J. David Singer of the University of Michigan graciously allowed the use of the name "Correlates of War" in the ICOW project's name when the project first began in the late 1990s. It should be noted that Singer, the Correlates of War project, and the University of Michigan, Penn State University, University of Illinois, and UC-Davis (all of which have hosted COW at some point in time) bear no responsibility for any decisions or errors that might be made by the ICOW project; such responsibility lies entirely with Paul Hensel, Sara Mitchell, and their co-authors and research assistants associated with the ICOW project.

Project Funding

Funding for the territorial claims data (in the form of research assistants) has generally been provided by the political science departments at Florida State, Iowa, and North Texas. Paul Hensel received a small Summer 1999 grant from FSU's Committee on Faculty Research Support (COFRS) to cover initial research on river claims, and a small Summer 2015 grant from UNT to cover preliminary research on identity claims. He and Sara Mitchell have received National Science Foundation (NSF) grants in 2001, 2002-2004, and 2010-2013 to cover data collection on territorial, river, and maritime claims. They also received a US Agency for International Development (USAID) grant for 2013-2014 (with Andrea Gerlak and Neda Zawahri) to cover additional data collection on treaties and institutions related to river and maritime claims, and a Department of Defense - Minerva Research Initiative grant for 2015-2017 (with Krista Wiegand and Andy Owsiak) to collect data on identity claims. Hensel also received a relatively small 2008 grant from the Northeast Asian History Foundation for work exploring the relationship between colonial legacies and territorial claims, although restrictions on the grant greatly limited the use of that grant's funds for the purposes of data collection.

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Endorsement of Specific Claims

The project's co-directors wish to emphasize that neither the ICOW project nor its participants take or endorse any official positions with respect to any of the claims in our data set. We are attempting to identify cases where nation-states have disagreed over specific issues in the modern era, as well as measuring what made those issues valuable to them and studying how they chose to manage or settle those issues. We have no interest in promoting or supporting any specific position on any of these claims, and we instruct our research assistants to make sure that any personal opinions they might have do not affect their research or coding.

It is also important to emphasize that the ICOW project's research and coding of individual cases is not influenced in any way by the views or opinions of any funding agencies or other organizations or institutions. Most of the research assistants who have worked on the project over the years have been paid for by the departments where the project's directors were employed, which have no political agenda with respect to any of the cases in the ICOW data, but we have also received external grants to assist in data collection. In no case have the sources of those grants made any effort to dictate how we should code any of the cases in our data set, or for that matter whether certain cases should or should not even be included in the data. Furthermore, even if a funding agency were to seek to influence our coding decisions, we would not comply; our purpose here is to provide an impartial compilation of data on territorial, river, maritime, and identity claims, not to support any country's views on any specific claim(s).

Issue Data Sets

Data Set Requirements

Because one of the ICOW project's primary goals is the generation of systematic data on a variety of different types of issues dividing nation-states, the project will eventually produce numerous data sets that are fully compatible with each other. That is, each ICOW data set will follow the same format, contain the same type of variables, and contain data on contention over comparable types of issues.

(1) The first (and most important) requirement for each ICOW data set is explicit evidence of contention involving official representatives of two or more nation-states over some type of issue. In the case of the ICOW territorial claims data, this means evidence that official representatives of at least one state make explicit statements claiming sovereignty over a piece of territory that is claimed or administered by another state. Claims that are not made explicitly, are not made by official representatives of at least one state government, or do not involve at least one nation-state on each side of the claim are beyond the scope of the present data set.

(2) Second, each ICOW data set must be collectable without reference to the occurrence of militarized conflict over the issue in question. Most existing social science data sets that involve disputed issues begin by identifying cases of militarized conflict (disputes, crises, or wars) and then code the issues involved in each confrontation. One of the most important contributions of the ICOW project, though, lies in the ability to test propositions on the propensity of different issue types to lead to militarized conflict, which can not be done if the data collection only includes issues that actually lead to such conflict. The ICOW territorial claims data set thus includes all identifiable cases where two or more states are involved in a claim over territory -- regardless of whether or not this claim eventually led to militarized conflict (or any other type of interaction).

(3) A third requirement for each ICOW data set is that data must be collectable on some type of measure of issue salience. That is, scholars using the data set must have some way to distinguish between claims of higher and lower salience. The ICOW territorial claims data set offers numerous variables that may be used to distinguish claims by issue salience, including the area and population of the claimed territory, the existence of resource, ethnic, or religious bases for the claim, and whether the claim involves mainland or offshore territory, homeland or colony/possession territory, and all of the target state, part of the target state, or merely the precise location of the border.

(4) Finally, each issue covered by the ICOW project must be amenable to data collection on attempts to manage the issue(s) in question. Another important contribution of the ICOW data is the ability to test propositions on the ways that states attempt to manage or settle their disagreements over different types of issues. For the ICOW territorial claims data, this includes all attempts to settle a territorial claim through bilateral negotiations or through third party assistance (such as mediation, arbitration, or adjudication).

Current Data Sets

The ICOW project is actively involved in collecting data on three types of issues: territorial, river, maritime, and identity claims. Each of these data sets is addressed in a separate page on this web site:

Beginning in 2019, we have started publishing quarterly reviews of events occurring in any of these four issue types during three-month periods. These reviews describe such events as the beginning of new claims, the occurrence of military or other provocations in the disputed territory, and attempts to manage or settle the issues peacefully. Besides posting each quarterly review at the above link, we also offer a DuckDuckGo custom search that allows users to search for reviews that contain such terms as names of territories, countries, or leaders. (For now, this is limited to ICOW's quarterly reviews of news over territorial, river, maritime, or identity claims, covering events since the beginning of 2019. In the future, we plan to expand this search to include access to summary web pages for each of the more than 1200 claims identified by the ICOW project, which will be created as part of the next external grant that the ICOW project receives.)

Previous Data Sets

Another data set is no longer being collected actively:

Supplementary Data Sets

Beyond the issues data sets described above, the ICOW Project has also collected several supplementary data sets to help in subsequent data collection and analysis. While not directly involving issues, these data sets are important for testing various issue-related hypotheses, as well as for collecting data using historical reference sources.

(Tentative) Schedule of Future Data Releases

The current release of the full ICOW data (including territorial, river, and maritime claims and including peaceful settlement attempts) is version 1.10, but the territorial claims data version 1.20 (all regions of the world from 1816-2001 but no peaceful settlement attempt data) is available at the Journal of Peace Research web site as an archive related to our 2017 publication summarizing that data set. We have a draft of all of the remaining data for territorial claims and river claims for the entire world through 2001, and maritime claims for all but Africa, which we are currently verifying and cleaning with plans to release as soon as possible. This remaining data will be released as time allows (our only currently funded research assistants are being paid under the Minerva grant for identity claims data). Once all four data sets -- territorial (1816-2001), river (1900-2001), maritime (1900-2001), and identity claims (1946-2017) -- are completed, we will pursue another grant that will allow us to bring all four up to date (likely through 2020), and will hopefully set the stage for releasing annual updates every spring.

Current Releases Territorial Claims River Claims Maritime Claims
ICOW Data version 1.10 (all 3 issues) Claims: Americas, Western Europe (1816-2001)

Settlement Attempts: Americas, Western Europe
Claims: Americas, Western Europe, Middle East (1900-2001)

Settlement Attempts: Americas, Western Europe, Middle East
Claims: Americas, Europe (1900-2001)

Settlement Attempts: Americas, Europe
ICOW Territorial Claims Data, version 1.20 Claims: Entire world, 1816-2001. This will be added to the next release of the full ICOW data, as described below, but is currently made available as a separate download at the Journal of Peace Research publication data archive (this is what we had previously called version 1.02 of the "provisional" data to distinguish it from the full 1.10 download with settlement attempts).

Settlement Attempts: Data on peaceful settlement attempts, which takes much longer to collect, will be released as described below.
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Future VersionsTerritorial ClaimsRiver ClaimsMaritime Claims
1.30 Claims: already completed and released for entire world

Settlement Attempts: add Eastern Europe
Claims, Settlement Attempts: add Eastern Europe, Middle East add Middle East
1.40 Claims: already completed and released for entire world

Settlement Attempts: add Africa
Claims, Settlement Attempts: add Africa Claims, Settlement Attempts: add Africa
1.50 Claims: already completed and released for entire world

Settlement Attempts: add Asia and Oceania
Claims, Settlement Attempts: add Asia and Oceania Claims, Settlement Attempts: add Asia and Oceania
2.00 * Add identity claims to the master download
Future * Extend all data sets through 2020
* Move toward annual updates each spring
Last updated: 17 November 2019
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