Frequently Asked Questions

This page contains some of the frequently asked questions about UCDP and UCDP data. You can find more questions and answers about the UCDP in the 2009 ICRC interview with Peter Wallensteen, the founder and former director of the UCDP (pdf) Pdf, 331 kB.. You are also welcome to contact UCDP at

  • What is a conflict?
  • What is an incompatibility?
  • Which conflicts are on the "unclear cases" list and why are they there?
  • When is a country sovereign?
  • How many conflicts were there in the world in 2021?
  • How are UCDP data collected?
  • How does terrorism fit into the UCDP’s categories of organized violence?
  • How does the UCDP deal with criminal violence, such as that in Mexico between drug cartels?
  • The Mexican Drug Wars have killed thousands of people; why are there so few non-state conflicts and so low fatality estimates for these conflicts?
  • How do I contact the UCDP regarding general questions, area experts and questions regarding UCDP datasets?
  • How and why does UCDP's and PRIO's data on battle deaths differ (pdf) Pdf, 692 kB. (Comment written by HSRP in 2012 after input by UCDP and PRIO.)

What is a conflict?

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. See also Wallensteen "Understanding Conflict Resolution” Sage (2015) p. 24-27

What is an incompatibility?

The concept of an incompatibility is central to the UCDP’s gathering of data on armed conflict, being an essential part of the definition. Theoretically an incompatibility is a disagreement between at least two parties where their demands cannot be met by the same resources at the same time. In other words, their positions are incompatible, since both sides lay claim to the same scarce resource(s). Such a disagreement is central to when social conflicts emerge, since an unlimited supply of a resource can satisfy all parties for all time.

In the UCDP’s definition of an armed conflict a stated incompatibility can concern government, territory, or both. In other words an armed conflict may erupt when two competing sides lay claim to the same piece of territory, or the same right to rule a country. These two categories have been arrived at empirically, through studying the main stated reasons for organised violence during the 1980s (Heldt, 1993, p.33-34).

Operationally the government category translates into an organised group stating (verbally or in writing) a wish to either change the political system of country or change the composition of a ruling government. In the territorial sphere it means the stated wish by an organised group to change the status of a specific piece of territory, for example changing what government controls it (interstate war), seceding from an existing state or acquiring more control over a piece of territory through autonomy arrangements (intrastate wars).

For a more detailed account of the operationalisation of the concept, see the UCDP definitions webpage. More theoretical background is available in Wallensteen, Peter, (2015), “Understanding Conflict Resolution”, 4th Edition, Sage Publications, London.

Which conflicts are on the “unclear cases” list and why are they there?

The UCDP unclear cases list contains conflicts that likely fulfil the three criteria in the definition, but where we lack information on one of the criteria. It could be missing information on how many battle-related deaths the conflict resulted in, that we could not find a stated incompatibility according to our definition, or that it is uncertain how organised the involved group is. If it is clear that a ‘conflict’ only fulfils two out of three criteria to be a proper conflict according to our definitions it is not included in the unclear list.

When is a country sovereign?

There can only be a minor armed conflict or a war in a country that is sovereign. Therefore the question of when a country is considered to be sovereign of high importance.

UCDP defines a state as: either an internationally recognised sovereign government controlling a specified territory, or an internationally unrecognised government controlling a specified territory whose sovereignty is not disputed by another internationally recognised sovereign government previously controlling the same territory.

Basically this coincides with the list of UN member states, with the addition of a few non-members such as Taiwan. These are states both de jure and de facto. If we are dealing with a non-recognised entity, or a de facto state, it can meet the criteria of a state as defined here, if no other state claims that territory - given that the other state once used to control the entity.

Each state is given a country code, the country codes are taken from Gleditsch & Ward (1999). However in some cases we do not have the same date for the country sovereignty.

Kristian Gleditsch definition

“In essence, we consider a state to be an independent polity if it:
a) has a relatively autonomous administration over some territory
b) is considered a distinct entity by local actors or the state it is dependent on, and
c) has a population greater than 250 000”

“Many cases of states that are de facto independent such as Chechnya, Somaliland, Transdniestra, and the Turkish Republic of Northern Cyprus have not been included since they are recognized by at most one other state.”

COW definition

Another well used list of country codes is the one used by Correlates of War (COW).

Singer and Small (1972:20) considered two criteria before 1920, namely whether candidates had a population greater than 500 000 and whether entities were “sufficiently unencumbered by legal, military, economic, or political constraints to exercise a fair degree of sovereignty and independence”. In practice, formal diplomatic relations with Britain and France at or above the level of chargé d’affaires in the capital city was used to determine whether states were independent members of the interstate system. After 1920, Singer and Small (1972:21) relied on whether a nation “either: (a) was a member of the League of Nations or the United Nations at any time during its existence, or (b) met the half-million population minimum and received diplomatic missions from any two (rather than the specific two) major powers.” In addition to the explicit criteria, the COW project excludes and includes a number of states based on ad hoc decisions.

UCDP have a different sovereignty date for some conflicts




25 June 1991 declares independence

27 April 1992 the new constitution of Yugoslavia




3 Mars 1992 declares independence

27 April 1992 the new constitution of Yugoslavia




30 August 1991 becomes independent
21 December 1991

How many conflicts were there in the world in 2021?

In 2021, there were 54 active state-based conflicts in the world, causing at least 25 battle-related deaths. For more information see Davies, Shawn, Therese Pettersson & Magnus Öberg. 2022. "Organized violence, 1989-2021 and drone warfare". Journal of Peace Research. 59(4).

The conflicts that were active in 2021 are listed below, in alphabetical order, with incompatibility in parenthesis:


  • Azerbaijan (territory: Artsakh)
  • Ukraine (territory: Novorossiya)

Middle East

  • Egypt (territory: Islamic State)
  • Iran – Israel (government)
  • Iran (government)
  • Iraq (government)
  • Israel (territory: Palestine)
  • Syria (government)
  • Syria (territory: Islamic State)
  • Turkey (territory: Kurdistan)
  • Yemen (government)


  • Afghanistan (government)
  • Afghanistan (territory: Islamic State)
  • India (government)
  • India (territory: Kashmir)
  • Indonesia (territory: West Papua)
  • Kyrgyzstan – Tajikistan (territory: Common border)
  • Myanmar (government)
  • Myanmar (territory: Kachin)
  • Myanmar (territory: Karen)
  • Myanmar (territory: Karenni)
  • Myanmar (territory: Kokang)
  • Pakistan (governemnt)
  • Pakistan (territory: Balochistan)
  • Pakistan (territory: Islamic State)
  • Philippines (government)
  • Philippines (territory: Islamic State)
  • Thailand (territory: Patani)


  • Burkina Faso (government)
  • Burkina Faso (territory: Islamic State)
  • Burundi (government)
  • Cameroon (territory: Ambazonia)
  • Cameroon (territory: Islamic State)
  • Central African Republic (government)
  • Chad (government)
  • Chad (territory: Islamic State)
  • DR Congo (government)
  • DR Congo (territory: Islamic State)
  • Ethiopia (government)
  • Ethiopia (territory: Oromiya)
  • Kenya (territory: Northeastern Province and Coast)
  • Mali (government)
  • Mali (territory: Islamic State)
  • Mozambique (territory: Islamic State)
  • Niger (government)
  • Niger (territory: Islamic State)
  • Nigeria (government)
  • Nigeria (territory: Islamic State)
  • Nigeria (territory: Biafra)
  • Somalia (government)
  • Somalia (territory: Islamic State)
  • South Sudan (government)
  • Sudan (government)


  • Colombia (government)

See the UCDP Conflict Encyclopedia (UCDP database) for more information on all of these conflicts.

How are UCDP data collected?

UCDP datasets on organized violence are updated and published on the website at least once a year, usually in June or July. If you wish to receive an e-mail that informs you of one updates are released, please join our mailing list.

Data collection is carried out in four stages:

1. The first stage of data collection is carried out by keying in a specific string of search words related to organized violence into the online Factiva Global News Database. Factiva carries over 30 000 different newswires, newspapers and other sources and has global coverage. For each country around the globe a specified set of sources is selected to provide the best coverage of news events possible. These sources always include at least one of the major newswires (Reuters, AFP, Xinhua, EFE) and BBC Monitoring; the latter source picking up local newspapers, and television and radio broadcasts. This exercise produces a number of news articles (commonly between 50 000 and 80 000) that are then downloaded by human coders and manually sorted. The information gathered is then coded according to the UCDP’s criteria for the different types of organized violence, taking heed to possible biases in reporting and any other aspects that may affect the reliability of the sources.

2. In the second stage the coders turn to other types of material available. This stage includes reading through newly published books and case studies, journals such as the Africa Research Bulletin and Africa Confidential, NGO publications (Human Rights Watch, Amnesty etc.) as well as available online databases within the sphere of organized violence. This information is then manually coded in the same way as in stage one, with for example estimates of deaths and considerations regarding incompatibilities being updated according to the new input.

3. If something still remains unclear in regard to which actors are fighting, the number of deaths, or if any other unclear factors are present, the UCDP makes use of its extensive network of regional experts. These are contacted with queries regarding any unclear matters and asked to weigh in with their expertise regarding specific groups, countries, regions, or any other aspect.

4. Lastly, the data that has been collected is scrutinised and checked by the UCDP’s project managers and the program’s directors, who have the final say in what data will enter the database and the datasets.

For a discussion on media bias, see Nick Dietrich & Kristine Eck (2020): Known unknowns: media bias in the reporting of political violence, International Interactions, DOI: 10.1080/03050629.2020.1814758.

How does terrorism fit into the UCDP’s categories of organized violence?

The UCDP does not make use of the term ‘terrorism’ to classify any type of violence. Each act of organized violence (meaning that it is carried out by a group that is organized according to certain criteria) is instead viewed through the lens of targets; are the targets other states, representatives of other organized groups or civilians?

In terms of the targeting of civilians the UCDP’s category of ‘one-sided violence’ often overlaps with definitions of terrorism with a lethal outcome. Any actor directly targeting and killing civilians are perpetrating one-sided violence. This also includes governments of states; a type of actor that according to many definitions of terrorism cannot be ‘terrorists’.

Attacks targeting a state, or another organized group, are labelled under the ‘state-based violence’ and ‘non-state violence’ labels respectively. Acts of violence targeting representatives or representations of the state are thus not labelled ‘terrorism’.

Likewise, no single actor is thus categorised as being ‘terrorist’.

As an example one can look at the events of 9/11. Three planes crashed into building in the USA; two into the World Trade Center and one into the Pentagon. The two planes flying into the World Trade Center are viewed as being acts of one-sided violence, since the World Trade Center is not a military target or a representation of the government of the USA. The third plane, which crashed into the Pentagon, is, however, coded as state-based violence as the Pentagon is a military installation.

How does the UCDP deal with criminal violence, such as that in Mexico between drug cartels?

The UCDP does not apply any labels regarding the nature of organized violence. Violence is thus not categorised according to any possible ‘political’ as opposed to ‘criminal’ goals. There is little logic to claiming that cattle-rustling and land clashes in Kenya are political whilst battles over the drug market and urban turf in Mexico are criminal.

Instead, the UCDP looks at whether or not those clashing are organized into identifiable groups. If this is the case, and clashes between two such actors cause 25 or more deaths in one calendar year, a non-state conflict is registered in UCDP data.

The Mexican Drug Wars have killed thousands of people; why are there so few non-state conflicts and so low fatality estimates for these conflicts?

The UCDP is aware that the figures given for the war between the cartels in Mexico are very low. Unlike much organized violence in the world, however, the fighting between cartels in Mexico is not overt in the sense that none of the actors wish to claim ‘credit’ for their actions. The UCDP needs to clearly identify the perpetrators of different acts of violence to be able to record them; something which is difficult in a context where the thousands of deaths mainly turn up as dead bodies found in the mornings. This is the case for much of the gang-related fighting that plagues mainly urban areas. Such violence is extremely difficult to code with the UCDP’s method, and those wishing to study it would do better to rely on criminal statistics.

How do I contact the UCDP regarding general questions, area experts and questions regarding UCDP datasets?

For questions regarding our data please contact us by e-mail,