COW War Data, 1816 - 2007 (v4.0)

Overview 

The COW Project introduced COW Wars v4.0, 1816-2007 in 2010. The paper “The COW Typology of War: Defining and Categorizing Wars (Version 4 of the Data)” by Meredith Reid Sarkees gives an overview of the COW war typology, the descriptions of the basic variables, coding rules and some of the changes since “Resort to Arms.” In March 2010, the New COW War List was released. On June 30, 2010, the Non-State War Data (v4.0) became available. On October 28, 2010, the Intra-State War Data (v4.0) was released and on April 6, 2020 the Intra-State War Data (v5.1) became available online. On March 1, 2011, the Inter-State War Data (v4.0) became available online. Finally, we released the Extra-State War Data (v4.0) on December 8, 2011. 

Citation

Sarkees, Meredith Reid and Frank Wayman (2010). Resort to War: 1816 - 2007. Washington DC: CQ Press.

Questions and Feedback

The war data sets are hosted by Meredith Sarkees, Global Women's Leadership in International Security, and Frank Wayman, University of Michigan-Dearborn, under the COW Data Set Hosting Program. In case of questions, they may be contracted by email at sarkees@sbcglobal.net and fwayman@umich.edu.

 

Previously, the Correlates of War (COW) Project has examined only wars that involved the government of a member of the interstate system (a state) in one form or another. The inclusion of non-state wars in the data presented here represents an attempt to broaden our understanding of war by including wars between or among non-state entities. Such entities include governments of other types of geopolitical units (GPUs), such as dependencies or non-state autonomous entities, that do not meet the criteria of system membership. They also might involve nonterritorial entities (NTEs) or non-state armed groups (NSAs) that have no defined territorial base.

The Correlates of War (COW) Project has utilized a classification of wars that is based upon the status of territorial entities, in particular focusing on those that are classified as members of the inter-state system (referred to as “states”). This dataset encompasses wars that predominantly take place within the recognized territory of a state, or intra-state wars.

The Correlates of War (COW) Project has utilized a classification of wars that is based upon the status of territorial entities, in particular focusing on those that are classified as members of the inter-state system (referred to as “states”). This dataset encompasses wars that take place between or among the recognized states, or inter-state wars.

The dyadic war dataset is built and fully compatible with the dyadic MID dataset (Maoz et al. 2019). It provides dyadic records of interstate wars over the period of 1816-2010, with a dyad-year unit of analysis. The dataset contains several innovations and changes compared to the war or MID datasets. Specifically,

• It applies the definition of war and war participation to a dyadic setting. A dyadic war is defined as a series of sustained and lethal battles between the armed forces of two states that is a part or the whole of an interstate war.
• For a dyadic war to be present both states must meet one or both of the following conditions: (1) the state must suffer 100 or more battle-related deaths in the battles with the other state, or (2) the state must deploy 1,000 or more troops in battles against the other state.
• War outbreak and war termination is defined in terms of battles, not in terms of declarations of war. A dyadic war starts on the start date of the first battle between the armed forces of the states making up the dyad. Accordingly, a dyadic ends on the last day of the last battle between the armed forces of the dyad.
• Each war is identified both in terms of its own dyadic code, and in terms of the dyadic MID of which it is a part.
• The data have been cleaned and each dyad that was part of a multilateral war was researched separately to determine whether it met the conditions stated above. The data also reflect a systematic comparison to the COW war data and another interstate war dataset (Reiter, Stam, and Horowitz 2014).
• To the extent possible, fatality data were broken down by individual state and dyad. However, in many cases involving a state that fights several opponents in the context of a multilateral war, such a breakdown is not possible. We provide “best” estimates of this breakdown.
• The data are fully compatible with the dyadic MID dataset. The dyadic war dataset is a proper subset of the dyadic MID dataset: every war in the dyadic MID dataset is part of a dyadic MID (but not vice versa).
• The outcome of the war is adjusted for the specific dyad. The winner in a dyadic war may have a different designation than the winning side in the COW war dataset.
• We assign specific roles to joiners in multilateral war: a joiner on the target side in a multilateral war may be the initiator against a state on the initiator’s side in the multilateral war.

Citation

Please cite: Zeev Maoz, Paul L. Johnson, Jasper Kaplan, Fiona Ogunkoya, and Aaron Shreve 2019. The Dyadic Militarized Interstate Disputes (MIDs) Dataset Version 3.0: Logic, Characteristics, and Comparisons to Alternative Datasets, Journal of Conflict Resolution (forthcoming). 

The Correlates of War (COW) Project has utilized a classification of wars that is based upon the status of territorial entities, in particular focusing on those that are classified as members of the inter-state system (referred to as “states”). This dataset encompasses wars in the middle category - wars that take place between a state(s) and a nonstate entity outside the borders of the state, or extra-state wars.