Armed Conflict Dataset (UCDP/PRIO)

Research project

Centre for the Study of Civil War (CSCW) at the International Peace Research Institute, Oslo (PRIO) and Uppsala Conflict Data Program (UCDP) at the Department of Peace and Conflict Research, Uppsala University, have collaborated in the production of a dataset of armed conflicts, both internal and external, in the period 1946 to 2008. Recent data generation projects have included more fully specified conflict start and end dates to aid in the study of the duration of violence; creating "conflict polygons" to pinpoint the geography of war within a given country; and adding figures for yearly combat deaths. Work on the dataset was supported by The World Bank's Development Economics Research Group as part of its project on The Economics of Civil War, Crime, and Violence. Both UCDP and PRIO offer a range of other datasets, compatible with the Armed Conflict Dataset. See Electronic resource below.


Armed Conflict Dataset (UCDP/PRIO)

Armed Conflict Dataset (UCDP/PRIO)


Armed Conflict Dataset






See below

Last reviewed


Data types and sources

Expert-coded variables and information based on historical sources.

Data download

Armed Conflict Dataset (UCDP/PRIO)


The variables in the dataset describe different aspects of armed conflict, such as: year of observation, sides, issues, location, type and start and end dates. Armed conflict is defined as a contested incompatibility that concerns government and/or territory where the use of armed force between two parties, of which at least one is the government of a state, results in at least 25 battle-related deaths.

Geographical coverage

The database is in principle universal in scope with data for most countries and territories (including some that no longer exist).

Time coverage and updates

The dataset identifies armed conflicts in countries and territories between 1946 and 2008. The dataset was last updated in 2009


All variables are well documented in the project’s online available codebook. The dataset is also described in Gleditsch et al. (2002) and six annual updates have been published in the Journal of Peace Research: in September 2003 (Eriksson et al., 2003); September 2004 (Eriksson & Wallensteen, 2004); September 2005 (Harbom & Wallensteen, 2005); September 2006 (Harbom, Högbladh & Wallensteen, 2006); September 2007 (Harbom & Wallensteen, 2007); and September 2008 (Harbom, Melander & Wallensteen, 2008). The updates include some changes in the data published for previous years, and the database is adjusted accordingly. A complete list of these changes is found in the document Version History and Known Errata. Copies of previous versions are available online.

Access conditions and cost

Available free of charge.

Access procedures

Predefined table.

Data formats


Comparability and data quality

Armed conflict is often measured or defined according to number of battle deaths. Whereas the datasets in Correlates of War use the relatively high threshold of 1,000 battle-deaths, the UCDP/PRIO Armed Conflict Dataset has a lower threshold of 25 annual battle-deaths. The Armed Conflict Dataset further distinguishes between three types of conflicts - war, intermediate armed conflict, and minor armed conflict - based on a combination of quantitative and qualitative assessments In the Uppsala/PRIO data set, "war" involves at least 1,000 battle-related deaths per year, "intermediate conflict" has between 25 and 1,000 deaths per year and a cumulative total for the entire conflict of at least 1,000 deaths, but fewer than 1,000 in any given year, and "minor armed conflict" has at least 25 deaths per year and fewer than 1,000 deaths accumulated during the course of the conflict. The qualitative criteria refer to the type of incompatibility among the parties (a conflict over government or territory) and their organization. . The distinction between minor conflicts and major wars is a matter of significance for post-war economic reconstruction and growth. According to Suhrke et al (2005) the Armed Conflict Dataset is therefore useful both for analyzing the causes as well as the consequences in terms of the impact of aid and policies on economic growth after civil war.

In many cases it may be difficult to find reliable data on battle deaths. The underlying data used to construct the armed conflict database might therefore be subject to problems of comparability and measurement error. According to the codebook the Armed Conflict Dataset does not include unclear conflicts where information on key variables to the definition of conflict is uncertain or missing. Key variables are those related to the incompatibility, actors and intensity. In the codebook it is further noted that due to lack of sources there is a possible bias produced against the inclusion of conflicts in the earlier decades and in the less-developed world. The information also varies with regard to the level of precision. For the start date variables, the precision level is indicated in a separate variable.

Electronic resources

ACLED - Armed Conflict Location and Event Data

Uppsala Conflict Data Program (UCDP)


Eriksson, Mikael, Peter Wallensteen and Margareta Sollenberg. 2003. "Armed Conflict, 1989–2002." Journal of Peace Research 40(5): 593–607.

Eriksson, Mikael, and Peter Wallensteen. 2004. "Armed Conflict, 1989–2003." Journal of Peace Research 41(5): 625–636.

Gleditsch, Nils Petter; Peter Wallensteen, Mikael Eriksson, Margareta Sollenberg and Håvard Strand. 2002. "Armed Conflict 1946–2001: A New Dataset." Journal of Peace Research 39(5): 615–637.

Harbom, Lotta; Stina Högbladh and Peter Wallensteen. 2006. "Armed Conflict and Peace Agreements." Journal of Peace Research 43(5): 617–631.

Harbom, Lotta and Peter Wallensteen. 2005. "Armed Conflict and Its International Dimensions, 1946–2004." Journal of Peace Research 42(5): 623–635.

Harbom, Lotta, and Peter Wallensteen. 2007. "Armed Conflict, 1989–2006." Journal of Peace Research 44(5): 623–634.

Harbom, Lotta, Erik Melander and Peter Wallensteen. 2008. "Dyadic Dimensions of Armed Conflict, 1946−2007." Journal of Peace Research 45(5): 697-710.

UCDP/PRIO Armed Conflict Dataset codebook Version 4-2009.

PRIO. 2009. Armed Conflict Dataset. Version History and Known Errata. Version 4-2009, 17 June 2009.

Suhrke, Astri, Espen Villanger and Susan L. Woodward. 2005. "Economic Aid to Post-Conflict Countries: A Methodological Critique of Collier and Hoeffler". CMI Working Paper WP 2005: 4.