Project Description

The Issue Correlates of War (ICOW) project is a research project that is collecting systematic data on contentious issues in world politics. More detail on the project's goals and theoretical underpinnings may be found in the papers generated by the project.

Project Participants

The ICOW 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. 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.

Beyond Paul and Sara, a number of other researchers have worked on ICOW data sets (listed here in alphabetical order). Some served as research assistant for a single semester or for a few summer research hours, while others -- most notably Allison, Brochmann, Frederick, Macaulay, Sowers, and Tures -- have spent substantial amounts of time working for the project over several years:

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. 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, as well as (with Andrea Gerlak and Neda Zawahri) a US Agency for International Development (USAID) grant for 2013-2014 to cover additional data collection on treaties and institutions related to river and maritime 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 limited the use of that grant for the purposes of data collection.

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The Project's Name

J. David Singer of the University of Michigan was kind enough to allow 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, and University of Illinois (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.

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 co-directors have been employed, which have no political agenda with respect to any of the cases in the ICOW data, but we have also received several 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, and maritime 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 regime claims. Each of these data sets is addressed in a separate page on this web site:


Two other types of issues have been collected, or will soon be collected:

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 ICOW data is version 1.10, but we have been collecting a great deal of information on each of the three current issue types (territorial, river, and maritime claims). We are currently planning the following schedule for releasing new data, although please note that the timing of these releases may change if the necessary data collection and cleaning has not yet been finalized:

Current ReleasesTerritorial ClaimsRiver ClaimsMaritime Claims
ICOW Data version 1.10 (all 3 issues) Americas, Western Europe (1816-2001) Americas, Western Europe, Middle East (1900-2001) Americas, Europe (1900-2001)
ICOW Territorial Claims Data, provisional version 1.01 Territorial claims data for the entire world, 1816-2001. This includes the list of claims, claim salience measures, and militarization of claims. Data on peaceful settlement attempts, which takes much longer to collect, will be released as described below.
Future VersionsProjected DateTerritorial ClaimsRiver ClaimsMaritime Claims
1.20 Spring 2015 add Eastern Europe add Eastern Europe --
1.30 Summer 2015 add Middle East -- add Middle East
1.40 Fall 2015? add Africa add Africa add Africa
1.50 Late 2015/Early 2016 add Asia and Oceania add Asia and Oceania add Asia and Oceania
2.00 Summer 2016? extend all three data sets through 2010
2.10 Late 2016/Early 2017? extend all three data sets through 2015

http://www.paulhensel.org/icow.html
Last updated: 21 February 2015
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