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UCDP is the Uppsala Conflict Data Program, a research programme at Uppsala University that collects and publishes data on organised violence. This guide is for researchers, students and data librarians who need to know which UCDP dataset to download, how UCDP defines conflict and one-sided violence, and how its API works. (Searching for the mortgage portal? See the short note below.)
What UCDP is
UCDP is part of the Department of Peace and Conflict Research at Uppsala University, Sweden. Its own page describes it as widely regarded as the world’s leading source of data on organised violence and as the longest-running active effort dedicated to collecting and maintaining conflict data. Data collection began in 1979, and the work was formalised in the mid-1980s as the Conflict Data Project. UCDP is also part of the Demscore e-infrastructure.
Its flagship dataset is the UCDP GED, a global event-level dataset that can be explored through the UCDP Conflict Encyclopedia. For questions, the programme lists [email protected] as its contact address.
UCDP in a mortgage context
In US mortgage lending, “UCDP” is a different thing: the Uniform Collateral Data Portal used for appraisal submissions, run by Fannie Mae and Freddie Mac. Questions such as what UCDP means in a mortgage, or where to find a Freddie Mac UCDP authorization code, are answered by those organisations, not by the Uppsala programme. Start at the Uniform Collateral Data Portal pages on singlefamily.fanniemae.com or sf.freddiemac.com. The rest of this page covers only the Uppsala Conflict Data Program.
How UCDP defines conflict
UCDP publishes its definitions on a dedicated page. Each of the three main categories has a threshold of at least 25 deaths in a calendar year:
- State-based armed conflict (also called “armed conflict”): 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.
- Non-state conflict: the use of armed force between two organised armed groups, neither of which is the government of a state, resulting in at least 25 battle-related deaths in a year.
- One-sided violence: see the next section.
So the answer to “what is the definition of conflict according to the UCDP?” depends on the category: the common elements are organised armed force and the 25-death annual threshold, and for state-based conflict the added requirement of an incompatibility over government and/or territory.
What is one-sided violence?
One-sided violence is the deliberate use of armed force by the government of a state or by a formally organised group against civilians, resulting in at least 25 deaths in a year (UCDP definitions page). The distinguishing feature is that the targets are civilians rather than an opposing armed party, which is why it has its own dataset.
Which UCDP datasets exist and what they cover
The UCDP downloads page lists the datasets below. Coverage years and version numbers change with each release, so check the page for the current edition before citing; the coverage shown here is as read on 2026-11-07.
| Dataset | Coverage listed |
|---|---|
| UCDP Georeferenced Event Dataset (GED), Global | 1989-2025 (version 26.1 when read) |
| GED Candidate Events (monthly releases) | Release 26.0.9 (September 2026) when read |
| UCDP/PRIO Armed Conflict Dataset | 1946-2025 (version 26.1) |
| Dyadic Dataset | 1946-2025 |
| One-sided Violence Dataset | 1989-2025 |
| Non-State Conflict Dataset | 1989-2025 |
| Battle-Related Deaths Dataset | 1989-2025 |
| Violent Political Protest Dataset | 1989-2025 |
| Peace Agreement Dataset | 1975-2021 (version 22.2) |
| External Support Dataset | 1975-2017 (version 18.1) |
The Country-Year Organized Violence Dataset is also listed on the downloads page. The dataset names show the unit of analysis: the GED is the event-level dataset, the UCDP/PRIO Armed Conflict Dataset is the conflict series reaching back to 1946, the Dyadic Dataset is organised around pairs of opposing parties, and the Country-Year Organized Violence Dataset aggregates to the country-year. The series start in different years (1946 versus 1989), so a comparison across datasets must restrict itself to the overlapping period.
How to find and use UCDP data
- Open the Downloads page on ucdp.uu.se and choose the dataset that matches your unit of analysis (see the table above).
- Note the version number shown next to the dataset and record it in your methods or data citation, since releases are versioned and updated.
- To explore GED events before downloading, use the UCDP Conflict Encyclopedia.
- For programmatic or bulk access, use the UCDP API, which provides structured JSON access to the same data. Request an access token from the API maintainer, as the documentation instructs.
- Build requests as
https://ucdpapi.pcr.uu.se/api/<resource>/<version>?pagesize=x&page=x. The version is required in every call. - Send the token in the
x-ucdp-access-tokenheader. - Choose a resource:
gedevents,ucdpprioconflict,dyadic,nonstate,onesided,battledeathsororganizedviolencecy. - Read
TotalCountandTotalPagesin each response and followNextPageUrl(or iterate pages up toTotalPages) to retrieve the full result.
For citing a downloaded file, see how to cite a dataset and, for recording which release you used, versioning research datasets.
Strengths and limits
- Strengths. Long record (collection since 1979), published definitions, several units of analysis (event, dyad, country-year), and a versioned, JSON-based API.
- Threshold limit. Every category uses a 25-deaths-per-calendar-year threshold, so smaller or lower-intensity violence falls outside the conflict datasets by definition. Treat absence from UCDP as “below the threshold or outside the definition”, not as “no violence”.
- Definition limit. The categories are UCDP’s own (for example, battle-related deaths for state-based conflict); other projects define and count conflict differently, so numbers are not interchangeable.
- Coverage limit. Dataset start and end years differ, and some (Peace Agreement, External Support) end well before the present.
- Access limit. API use needs a token requested from the maintainer.
Alternatives: UCDP and the Correlates of War project
| Resource | What its own page says |
|---|---|
| UCDP (Uppsala University) | Collects and maintains data on organised violence; GED, UCDP/PRIO Armed Conflict and related datasets. |
| Correlates of War (COW) | “Facilitates the collection, dissemination, and use of accurate and reliable quantitative data” for international relations; recent releases include NMC v7, Arms Technology v1.1 and State System Membership v2024. |
The two are separate projects with separate datasets and coding rules. If you combine them in one analysis, cite each with its version and do not assume their conflict definitions match. For choosing where to deposit your own derived data, see how to choose an open data repository; the related terms open data and data repository explain the concepts.
FAQ
What does UCDP mean in a mortgage?
It stands for the Uniform Collateral Data Portal run by Fannie Mae and Freddie Mac. That is unrelated to the Uppsala Conflict Data Program; use the Fannie Mae or Freddie Mac pages for it.
What is one-sided violence?
Deliberate use of armed force by a state government or a formally organised group against civilians, causing at least 25 deaths in a year, per UCDP’s definitions.
Where can I find my Freddie Mac UCDP Authorization Code?
That belongs to the mortgage portal, not to the Uppsala programme. Freddie Mac’s single-family site (sf.freddiemac.com) is the place to ask.
What is the definition of conflict according to the UCDP?
A state-based armed conflict is a contested incompatibility concerning government and/or territory, with armed force between two parties (at least one a state government) causing at least 25 battle-related deaths in a calendar year. Non-state conflict and one-sided violence use the same 25-death threshold with different parties.
Sources
- Uppsala University, UCDP: uu.se/en/department/peace-and-conflict-research/research/ucdp (read 2026-11-07)
- UCDP definitions: uu.se UCDP definitions (read 2026-11-07)
- UCDP downloads: ucdp.uu.se/downloads (read 2026-11-07)
- UCDP API documentation: ucdp.uu.se/apidocs (read 2026-11-07)
- Correlates of War: correlatesofwar.org (read 2026-11-07)
