Girish Mahajan (Editor)

Uppsala Conflict Data Program

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Abbreviation  UCDP
Subsidiaries  SIPRI Yearbook
Founded at  Uppsala, Sweden
Website  UCDP
Uppsala Conflict Data Program

Parent organization  Department of Peace and Conflict Research, at Uppsala University
Staff  approximately 15 research assistants and researchers

The Uppsala Conflict Data Program (UCDP) is a data collection project on organized violence housed at Uppsala University in Sweden that has been collecting information on armed conflict since 1946 and making it publicly available through its annual report, States in Armed Conflict. Beginning in Since 2004, the constantly-updated UCDP is also publicly available. The UCDP collects both quantitative and qualitative data on organized violence (e.g., fatality statistics, georeferenced event data, and armed actor and conflict descriptions) that is used by social science researchers, journalists, and policymakers.



The UCDP began recording information on ongoing violent conflicts in the 1970s. It became clear that more systematic and global data on armed conflicts was necessary for conducting research in the expanding academic discipline of peace and conflict studies.

Initially, the program collected data only on so-called "armed conflicts", defined as fighting exceeding 25 battle-related deaths between two actors of which at least one was a state. In later years, the data gathering grew, and the program also began collecting data on "non-state conflicts" (where neither party was a state) and "one-sided violence" (where an organized group attacked unarmed civilians).

The UCDP's data is published annually in such publications as the SIPRI Yearbook and the Journal of Peace Research. The UCDP also makes its data publicly available through its website and in its annual publication, States in Armed Conflict.


The UCDP is located at the Department of Peace and Conflict Research of Uppsala University in Sweden. The program is led by the Dag Hammarskjöld Professor of Peace and Conflict Research, Peter Wallensteen, and employs approximately 15 research assistants and researchers. A number of scholars and Ph.D. candidates are also attached to the program and tasked with carrying out research for the collection of conflict data. In addition to collecting data, the program disseminates knowledge on trends and dynamics of armed conflict to the public via lectures at academic and government forums.


The UCDP works closely with both the Peace Research Institute Oslo (PRIO) and the Human Security Report Project, based within the School for International Studies at Simon Fraser University in Vancouver, British Columbia, Canada. The UCDP collaborates with PRIO to create its datasets and provides the Human Security Research Project with data for its annual publication, the Human Security Report. The UCDP's data is published annually in collaboration with the Stockholm International Peace Research Institute (SIPRI) and appears in the SIPRI Yearbook.


Hundreds of scholars have used the UCDP's data for research. The UCDP couples data collection with research on conflict resolution and the dynamics of conflicts. Much of the research done by UCDP staff is published in the UCDP's States in Armed Conflict annual report, the annual SIPRI Yearbook, and the Journal of Peace Research.

UCDP/PRIO Armed Conflict Database

The Armed Conflict Dataset is a joint project between the UCDP and PRIO that records armed conflicts from 1946–2012 that result in a minimum of 25 battle-related deaths and in which at least one actor is the government of a state. Data is collected by keying specific search words in the Factiva Database, an online resource containing over 10,000 different newspapers, newswires, and other sources, as well as published books, case studies, and journals (Africa Research Bulletin, Africa Confidential, NGO publications). There have been four versions of the dataset, with Version 4-2013 being the most recent.

Every armed conflict is classified as a dyad in the dataset and assigned an ID number. A dyad consists of two conflicting primary parties. Dyads can last multiple years and are coded for intensity level ("minor" for those with less than 1,000 deaths; "major" for those with more than 1,000 deaths), region (Americas, Asia, Middle East, Africa, Europe), incompatibility (government, territory, government and territory), and type (extrasystemic, interstate, internal, internationalized internal). The start date, end date, year, and location of conflict are also provided as well as the precision of the start and end date.

The conflict between the United States and Al-Qaeda is an example of a dyad from the dataset. The United States is the government or Side A, while Al Qaeda is the organized political group or Side B. The conflict has an ID number in the dataset of 224, was located in Afghanistan in the Middle East region, and is coded with an intensity level of a 2 (major conflict resulting in over 1,000 deaths) from 2001–2010.

Quantitative data from the dataset

Mean intensity of armed conflicts between 1946–2012: 1.272163966. Average number of conflict per year between 1946–2012: 36.48 armed conflicts. Year with the most armed conflicts: 1991 and 1992. Year with the least amount of armed conflicts: 1955. Region with the most armed conflicts: Asia. Most common type of armed conflict: Internal.


UCDP data has been published in the SIPRI Yearbook since 1988. Since 1993, a list of all armed conflicts also appears in the Journal of Peace Research. Data on non-state conflicts appears in the Human Security Report from 2004. The UCDP also releases (annually) its own report, States in Armed Conflict. UCDP data is also frequently used by journalists, government agencies, and other organizations to produce overviews of peace and conflict in the world. One prominent index that uses UCDP data is the Global Peace Index.

A battle-related death is one that is caused by combat between conflicting parties over a contested incompatibility. These deaths can be caused by traditional battlefield fighting, guerrilla activities, urban warfare, and any kind of bombardment of military units, cities, and villages. Guerrilla activities include hit-and-run attacks and ambushes, and examples of urban warfare include bombs, explosions, and assassinations. Targets of attacks are generally military, state institutions, and state representatives. However, civilians are collateral damage, and both military and civilian deaths are accounted for in the dataset.

UCDP has three ways of estimating battle-related deaths: best estimate, low estimate, and high estimate. The best estimate is the aggregate of the most reliable numbers for all battle-related incidents during a year. The low estimate is the aggregate of low estimates for all battle-related incidents during a year, and the high estimate is the aggregate of high estimates for all battle-related incidents during a year. These estimates are found in both conflict-year based datasets and dyad-year based datasets. The averages of deaths in the most recent of each kind of dataset are:

UCDP gathers and updates data on a yearly basis. They have datasets available from 1989 to 2012. Every event lists the date of the event, reporting source, primary source, actors involved, place of event, what happened, and the estimates of fatalities. The staff reads all the reports, and the information is entered manually. Furthermore, the aggregate results are compared to figures in official documents, special reports, and news media.

UCDP uses both printed and electronic public sources for gathering information. The main source is the Factiva Database that is composed of over 10,000 newspapers, newswires, and other sources from around the globe. UCDP uses at least one major newswire (Reuters, Xinhua, EFE) and BBC Monitoring. Additional sources include news agencies, newly published books, case studies, journals like Africa Research Bulletin, research reports, documents of international and multinational organizations, publications by NGOs such as Human Rights Watch and Amnesty International, and documents of fighting parties. Sources are judged according to the context in which they are published, and reports are traced back to the primary source to establish reliability.

UCDP's definitions of organized violence

The program divides armed conflict into three categories: "state-based conflict", "non-state conflict", and "one-sided violence".

State-based conflict refers to what most people intuitively perceive as "war"; fighting either between two states, or between a state and a rebel group that challenges it. The UCDP defines an armed state-based conflict as: "An armed conflict is 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 in one calendar year". The program's definition differs somewhat from other data collection programs, such as the Correlates of War Project, which only counts conflicts where at least 1,000 deaths have been recorded during one calendar year. In UCDP, data such an armed conflict is labelled as having the intensity level of "war", whilst armed conflicts that reap between 25 and 999 battle-related deaths are seen as having the intensity of a "minor" armed conflict.

Non-state conflicts are those conflicts in which none of the warring parties is a state. Examples of non-state conflicts include the Fatah–Hamas conflict of 2006 and 2007, inter-ethnic group conflicts such as the Lou Nuer–Murle conflict of 2009–2012, and inter-cartel violence in the Mexican Drug War.

One-sided violence is defined as: "The use of armed force by the government of a state or by a formally organized group against civilians which results in at least 25 deaths in a year". Examples include actions by the governments of Sudan, Myanmar, and Syria against civilians, as well as actions of non-state organizations such as Los Zetas, Al-Qaeda, and the Lord's Resistance Army against civilians.

List of state-based conflicts in 2011

In 2011, the UCDP reported 37 active state-based armed conflicts:

Europe • Russia (territory: Caucasus Emirate)

Middle East • Iran (government) • Iraq (government) • Israel (territory: Palestine) • Syria (government) • Turkey (territory: Kurdistan) • Yemen (government)

Asia • Afghanistan (government) • Cambodia, Thailand (territory: common border) • India (territory: Kashmir) • India (government) • Myanmar (territory: Karen) • Myanmar (territory: Kachin) • Myanmar (territory: Shan) • Pakistan (territory: Baluchistan) • Pakistan (government) • Philippines (territory: Mindanao) • Philippines (government) • Tajikistan (government) • Thailand (territory: Patani)

Africa • Algeria (government) • Central African Republic (government) • Ethiopia (territory: Ogaden) • Ethiopia (territory: Oromiya) • Ivory Coast (government) • Libya (government) • Mauritania (government) • Nigeria (government) • Rwanda (government) • Senegal (territory: Casamance) • Somalia (government) • Southern Sudan (government) • Sudan (government) • Sudan (territory: Abyei) • Uganda (government)

Americas • Colombia (government) • USA (government)

Out of these 37 armed conflicts, a total of six (Yemen, Afghanistan, Pakistan, Libya, Somalia and Sudan) reached the intensity level of "War", meaning that more than 1,000 battle-related deaths were recorded in 2011.

In 2012, six conflicts also reached the intensity level of "war".

  • Note: Fatality figures may be substantially lower than other stated estimates as UCDP data does not include fatalities from disease and/or war-time epidemics, or combine casualty figures between different types of armed conflicts. Additionally the figures in the tables represent the UCDP's "best estimate" figures and not its "high estimate" figures.
  • Criticism

    Edward Herman, Professor Emeritus of Finance at the Wharton School of the University of Pennsylvania, and his colleague David Peterson, who together co-authored The Politics of Genocide, have accused the UCDP of using "politicized [...] methodologies" in an effort to "minimize U.S.- and Western-led warmaking and killing." Exemplifying these assertions, they compare the classification of US involvement in Guatemala and the perception of Soviet involvement in Afghanistan by the program.

    UCDP on the internet

    The UCDP's homepage is located at The UCDP also has an on-line database of organised violence, accessible at The database provides free information on state-based and non-state conflicts, as well as one-sided violence. It also includes descriptive information on causes and histories of conflicts and one-sided violence and brief descriptions of rebel groups, governments, and related items.

    UCDP for iPhone and Android

    As of July 2010, the UCDP Conflict Database is available as an iPhone application and an Android application.


    Uppsala Conflict Data Program Wikipedia