UCDP One-sided Violence Codebook
Version 22.1
Uppsala Conflict Data Program
Department of Peace and Conflict Research
Uppsala University

This version compiled and updated by Therese Pettersson (2022)
Replacing the earlier versions by Marie Allansson and Mihai Croicu (2017), Therése Pettersson (2012), Joakim Kreutz(2008) and Joakim Kreutz & Kristine Eck (2005)

When using this data, please always cite:

Eck, Kristine & Lisa Hultman (2007). One-sided violence against civilians in war: insights from newfatality data. Journal of Peace Research 44(2): 233-246.
Davies, Shawn, Therese Pettersson & Magnus Öberg (2022). Organized violence 1989-2021 anddrone warfare. Journal of Peace Research 59(4).
When appropriate, also cite this codebook: Pettersson, Therese (2022) UCDP One-sided
Violence Codebook v 22.1 (https://ucdp.uu.se/downloads/).
Always include the Version number in analyses using the dataset.

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Contents
1.

Introduction ........................................................................................................................................... 3

2.

Definition of One-sided violence ........................................................................................................... 3
2.1.

One-sided violence ........................................................................................................................ 3

2.2

Fatality estimates ........................................................................................................................... 4

3.

Variables in the One-sided violence dataset .......................................................................................... 54.

Data Collection Methods ...................................................................................................................... 8

5.

Version name convention ...................................................................................................................... 86.

Format availability .................................................................................................................................. 97.

A note on UCDP ID changes ................................................................................................................ 92/9

1. Introduction
This document describes the One-sided Violence Dataset, a project within the Uppsala Conflict
Data Program (UCDP) at the Department of Peace and Conflict Research, Uppsala University.
The UCDP One-sided violence project has been developed with support from the Human
Security Report Project, Simon Fraser University, in Vancouver, Canada.
Case-specific information about the cases of one-sided violence is available at www.ucdp.uu.se
Questions regarding the definitions and the content of the dataset can be directed toucdp@pcr.uu.se

2. Definition of One-sided violence
2.1.

One-sided violenceOne-sided violence is the use of armed force by the government of a state or by a formallyorganized group against civilians which results in at least 25 deaths. Extrajudicial killings in custody
are excluded.
The separate elements of the definition are operationalized as follows:(1) Use of armed force: use of arms in order to exert violent force, resulting in death(1.1) Arms: any material means, e.g. manufactured weapons but also sticks, stones,fire, water, etc.
(2) 25 deaths: a minimum of 25 civilian deaths per year and per actor.
(3) Government: the party controlling the capital of the state.
(4) Formally organized group: any non-governmental group of people having announced a name for
their group and using armed force.
(5) State: a state is(5.1) an internationally recognized sovereign government controlling a specified territory,or(5.2) an internationally unrecognized government controlling a specified territory whosesovereignty is not disputed by another internationally recognized sovereign government
previously controlling the same territory.
(6) Civilians: unarmed people who are not active members of the security forces of the state, ormembers of an organized armed militia or opposition group. Government officials, such as
members of parliament, governors, and councilors, are also excluded and are instead seen as
representatives of the government of a state.

3/9Note that the UCDP definition of civilian does not refer to the definition of civilian underinternational law.
(7) Extrajudicial killings in custody: when the government of a state kills a person in its custody.
(7.1) custody: when the person is located in a prison or another type of governmental
facility.

2.2

Fatality estimates

UCDP codes three different fatality estimates – low, best and high – based on the reliability ofreports and the conflicting number of deaths that can be reported for any violent event.
•••Low estimate: The UCDP Low estimate consists of the aggregated low estimates for all
incidents of one-sided violence during a year. If different reports provide different estimatesand a higher estimate is considered more reliable, the low estimate is also reported if
deemed reasonable.
Best estimate: The UCDP Best estimate consist of the aggregated most reliable numbers for
all incidents of one-sided violence during a year. If different reports provide different
estimates, an examination is made as to what source is most reliable. If no such distinction
can be made, UCDP as a rule include the lower figure given.
High estimate: The UCDP High estimate consists of the aggregated high estimates for all
incidents of one-sided violence during a year. If different reports provide different estimatesand a lower estimate is considered more or equally reliable, the high estimate is also
reported if deemed reasonable. If there are incidents when there is some uncertainty about
what parties have been involved, these are also included in the high estimate.

It is the best estimate one-sided violence that determines whether or not an actor will be includedin the UCDP One-sided Violence data (i.e. the best estimate needs to be 25 or higher).

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3. Variables in the One-sided violence datasetVariable nameContentType

conflict_id

A unique conflict identification code for each individual Integer
observation of one-sided violence in the dataset. Used onlyfor merging purposes across the UCDP datasets.

dyad_id

A unique dyad identification code for each individual Integer
observation of one-sided violence in the dataset. Used onlyfor merging purposes across the UCDP datasets.

actor_id

This is a numerical identifier that describes each individual Integer
actor. The dataset makes use of the general actor/side ID
employed by UCDP.
Warning: Unlike the previous versions of the dataset, thisvariable is NO LONGER the Gleditsch and Ward identifier(GWNo) for the state actors. Use gwnoa below instead!
From version 17.1 of the dataset and onwards, the ID
system for conflicts, actors and dyads changed in order tomake it unique across all UCDP core datasets and all
UCDP types of violence. To download a conversion tablecontaining new and old IDs, visit
http://ucdp.uu.se/downloads/.

coalition_components

If multiple actors are perpetrating violence together as a String
joint (temporary) coalition, the components of thecoalition (in the form of a string of actor IDs) are listed
here.

actor_name

The government of a state or the name used by a formally Stringorganized group perpetrating the violence.
Comma separated if multiple.

actor_name_fulltext

The full original name of the actor, in English.

Stringactor_name_mothertongue

The full original name of the actor, in mother tongue.

Stringyear

The calendar year of observation. UCDP employs a Integer
threshold for inclusion of at least 25 deaths caused by onesided violence for each actor in a calendar year.
There are cases when actors are responsible for one-sided
violence of a scale that does not meet the threshold.

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These observations are coded as absence of one-sided
violence.
Episodes that do not exceed the threshold for actors thathave exceeded the threshold at least once during the 19892021 period can be traced through the UCDP GED
dataset.
best_fatality_estimate

The best fatality estimate for the given episode.

IntegerThis is an automatic aggregation (summing) of all the Bestfigures for all incidents reported for the given dyad-year in
the UCDP Georeferenced Event Dataset.
low_fatality_estimate

The low fatality estimate for the given episode.

IntegerThis is an automatic aggregation (summing) of all the Low
figures for all incidents reported for the given dyad-year in
the UCDP Georeferenced Event Dataset.
high_fatality_estimate

The high fatality estimate for the given episode.

IntegerThis is an automatic aggregation (summing) of all the Highfigures for all incidents reported for the given dyad-year in
the UCDP Georeferenced Event Dataset.
is_government_actor

For some purposes, it may be necessary to disaggregate Integer
between government and non-governmental actors in thedataset. This variable records if the actor is the governmentof a state and is coded as 1 for government actors and 0
for non-governmental actors.

location

The countries where this episode of violence took place.
Comma-separated if multiple.
WARNING: This variable SHOULD NEVER be used forany geographical or spatial analyses of conflict, as thedistribution of violence as well as the relative magnitude ofviolence by country is not captured. In effect a country islisted here if even one dead in the given conflict has
occurred in that country.
In fact, UCDP provides much better geographic coverageof conflict (including distribution of violence for eachconflict and each country) in the UCDP Georeferenced
Event Dataset (GED).
Like the UCDP One-Sided Violence Dataset, GED is globaland covers the same period (1989-2021).

6/9Stringgwno_location

The Gleditsch and Ward code for the countries where this String
episode of one-sided violence took place. Commaseparated if multiple.
WARNING: This variable SHOULD NEVER be used forany geographical or spatial analyses of conflict, as thedistribution of violence as well as the relative magnitude ofviolence by country is not captured. In effect, a country islisted here if even one dead in the given conflict has
occurred in that country.
In fact, UCDP provides much better geographic coverageof one-sided violence (including distribution of violence foreach dyad and each country) in the UCDP Georeferenced
Event Dataset (GED).
Like the UCDP One-Sided Violence Dataset, GED is globaland covers the same period (1989-2021).

gwnoa

The Gleditsch and Ward country identifier if the actor Integer
perpetrating one-sided violence is a state.
Empty otherwise.

regionThe continents (regions) where violence took place:String

1 = Europe (GWNo: 200-399),
2 = Middle East (GWNo: 630-699)
3 = Asia (GWNo: 700-999)
4 = Africa (GWNo: 400-626)
5 = Americas (GWNo: 2-199).
version

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The version of the dataset: 22.1

Float

4. Data Collection Methods
This dataset is the result of an automatic filtering and aggregation of the UCDP GeoreferencedEvent Dataset from incident/event level to the actor-year level.
The original reporting underlying the dataset is collected from three sets of sources:
1. global newswire reporting
2. global monitoring and translation of local news performed by the BBC
3. secondary sources such as local media, NGO and IGO reports, field reports, books etc.
The process is done in a "two-pass" system, first by consulting newswire sources for the entire
globe then by consulting local/specialized sources based on information obtained from the firstpass.
A detailed description of the process including a detailed description of the passes and the searchstrings employed is provided in the UCDP GED Codebook version 22.1, Section 4.

5. Version name convention
In 2017, the version name convention was changed, giving all UCDP datasets the same version
number across the board. This was done so that users more easily can see which UCDP dataset
corresponds with which.
This codebook corresponds to Version 22.1 of the UCDP One-sided Violence Dataset. For every
new release, substantial changes will be documented in a separate document. This should be
helpful to researchers trying to replicate a particular study. We recommend that whenever thisdataset is used, the version number should be cited.
The version number is a combination of a year and a number. The year refers to when thedataset is updated with new observations. If there are changes in the data between yearly
updates, or if there are substantial changes in the structure of the dataset, the number behind theyear is incremented.

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6. Format availability
The data is available in CSV (respecting the RFC 4180 specification), Excel (XLSX), Rdata (3.xversion) and STATA (2010 format).
The data is available for machine-to-machine interaction through a public API. Documentation for
how to use the API is available at http://ucdp.uu.se/apidocs.

7. A note on UCDP ID changes
As of version 17.1 of all UCDP datasets, the ID system for conflicts, actors and dyads waschanged in order to make them unique across all UCDP core datasets and all UCDP types ofviolence. This allows easier aggregation and disaggregation of data as well as simplify data
management for users, especially when combining multiple UCDP products together.
For example, a non-state conflict cannot have the same ID as a (different) state-based conflict or
as a case of one-sided violence (which was possible before).
Further, actor/side IDs representing a government were decoupled from their corresponding
Gleditsch and Ward country codes (GWNo). Gleditsch and Ward country codes for statesides/actors are provided in separate columns from their sides ID (i.e. side_a_id is different fromgwno_a but represents the same entity).
This means all IDs used in the dataset from version 17.1 and onwards are no longer compatiblewith those in older versions of UCDP products. Further, this means that external products relying
on UCDP IDs for data management tasks will have to be adapted to work with the new IDsystems.
A conversion table between the new and old ID systems is available here:
http://ucdp.uu.se/downloads/.

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