In This Article Expand or collapse the "in this article" section Uppsala Conflict Data Program

  • Introduction
  • General Overviews
  • Core Conflict Data Releases
  • Conflict-Related UCDP Data Releases
  • Data Collection and Methodology
  • Debates, Critiques, and Provisos of UCDP
  • Extensions of UCDP Data

International Relations Uppsala Conflict Data Program
Kristine Eck
  • LAST REVIEWED: 24 May 2018
  • LAST MODIFIED: 24 May 2018
  • DOI: 10.1093/obo/9780199743292-0232


The Uppsala Conflict Data Program (UCDP) began collecting systematic data on interstate and intrastate armed conflict in 1978. It adopted two innovations that distinguished it from the Correlates of War program: (1) a lower fatality threshold of twenty-five deaths per year for inclusion, and (2) the requirement of an incompatibility. These definitional criteria are the same for both interstate and intrastate armed conflicts. UCDP’s annual list of armed conflicts was published in the SIPRI Yearbook from 1988 to 2017 and in the Journal of Peace Research since 1993. In 2002, the UCDP expanded its temporal coverage by backdating its list of conflicts to 1946 in collaboration with the Peace Research Institute Oslo (PRIO) (Gleditsch, et al. 2002, cited under Core Conflict Data Releases). In 2003, it expanded the scope of its data collection to also include one-sided violence (i.e., the deliberate killing of civilians) and nonstate conflict (i.e., fighting between two groups, neither of which is the government of a state). These data were discussed first in the Human Security Report 2005 and subsequently presented in detail in two separate articles: Eck and Hultman 2007 and Sundberg, et al. 2012 (both cited under Core Conflict Data Releases). In 2013, the UCDP released a georeferenced, event-level disaggregated version of its data called the UCDP GED (Georeferenced Events Dataset), presented in Sundberg and Melander 2013 (also cited under Core Conflict Data Releases). The UCDP GED data are publicly available via the UCDP webpage as static products (i.e., ready-made data sets), as a public application programming interface (API), and as a web visualization and exploration platform. These different formats facilitate accessibility for a wide variety of users. The UCDP has also released numerous conflict-related data sets on phenomena such as peace agreements, third-party mediation, etc., as static data sets. UCDP has been critiqued for its definitions and methodology, and a literature has arisen to compare different conflict data collection projects. The UCDP is one of the most cited academic resources on organized, collective violence and is frequently used in the policy, teaching, and media domains. Since 2009 Uppsala University provides assured funding for the UCDP, although external grants remain important for continued innovation. Notably, the UCDP Constitution precludes funding from defense industry sources.

General Overviews

These works provide background information on the history and development of the UCDP as an organizational entity.

  • Sundberg, Ralph, and Lotta Harbom. “Systematic Data Collection: Experiences from the Uppsala Conflict Data Program.” In Understanding Peace Research: Methods and Challenges. Edited by Kristine Höglund and Magnus Öberg, 91–113. London: Routledge, 2011.

    This book chapter discusses the connection between theory and UCDP’s operational definitions, construct validity, and data collection procedures.

  • Wallensteen, Peter. Peace Research: Theory and Practice. London: Routledge, 2011.

    This is an anthology of essays written by Peter Wallensteen, founder of the UCDP. It provides a thorough overview of the history and development of the UCDP.

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