UCDP Actor Dataset Codebook
Version 21.1
Uppsala Conflict Data Program
Department of Peace and Conflict Research
Uppsala University

This version compiled and updated by Therese Pettersson (2021)
When using this data, please always cite:

Pettersson, Therese, Shawn Davis, Amber Deniz, Garoun Engström, Nanar Hawach, Stina
Högbladh, Margareta Sollenberg & Magnus Öberg (2021). Organized violence 1989-2020, with a
special emphasis on Syria. Journal of Peace Research 58(4): 809-825
When appropriate, also cite this codebook: Pettersson, Therese (2021) UCDP Actor Dataset
Codebook v 21.1 (https://ucdp.uu.se/downloads/).
Always include the Version number in analyses using the dataset.

Contents
Introduction ................................................................................................................................................... 2
UCDP’s three categories of organized violence ............................................................................................ 3
State-based armed conflict ........................................................................................................................ 3
One-sided violence .................................................................................................................................... 3
Non-state conflict ...................................................................................................................................... 3
Definition of a state actor .............................................................................................................................. 4
Definition of a non-state actor ...................................................................................................................... 5
Rules guiding the differentiation between non-state actors ........................................................................... 6
Variables in the Actor Dataset ...................................................................................................................... 7
Version name convention ............................................................................................................................ 11
A note on UCDP ID changes ...................................................................................................................... 11
References ................................................................................................................................................... 11

Introduction
This codebook presents the variables in the UCDP Actor Dataset, and clarifies the definitions.
Actor-specific information is also available at www.ucdp.uu.se. Questions regarding the definitions
and the content of the dataset can be directed to ucdp@pcr.uu.se
The unit of analysis in the UCDP Actor Dataset is a unique actor. The dataset is constructed so
as to be compatible with all UCDP’s datasets on organized violence (the UCDP Geo-referenced
Events Dataset, the UCDP/PRIO Armed Conflict Dataset, the UCDP Dyadic Dataset, the UCDP
Battle-related Deaths Dataset, UCDP One-sided Violence Dataset and the UCDP Non-state
Conflict Dataset) and thus contains all actors – both state – and non-state ones – included inthese datasets. As such, it functions as an inventory of actors in UCDP data, but its scope isbroader than that. The UCDP Actor Dataset also ascribes unique actor IDs to all actors, identifies
which types of organized violence the actor has been involved in (state-based, non-state and/or
one-sided) and, more particularly, in which conflicts and dyads of state-based, non-state and/or
one-sided violence.
Furthermore, the dataset contains information about the name history of the actor, outlining themost current name (which is also the name used in the data), the original name (i.e. the name thegroup had when it entered UCDP data for the first time) and any possible name changes between
the two. In addition, the dataset also includes information on the group’s origins and alliances.
First, information is given about whether the non-state actor was created by splintering off fromanother actor recorded in UCDP data, and, if so, which actor. Second, information is included
on whether the actor is created by a temporary split in the original actor. Third, the dataset also
includes data on whether the non-state actor ever entered into an alliance with another recorded
non-state actor in UCDP data (which would beget a new non-state actor), as well as the nameof said alliance. Finally, information is given about whether a non-state actor has joined a groupalready registered in UCDP data, not creating a new alliance but merely entering the other group.
For non-state actors, information can also be found on temporary coalitions i.e. when non-state
actors fight together in non-state conflict or one-sided violence without creating a formal alliance.

UCDP’s three categories of organized violence
Below follows a brief introduction to the three types of organized violence that UCDP collects
information on, and that make up the datasets to which the UCDP Actor dataset corresponds.

State-based armed conflict
An armed conflict is defined as a contested incompatibility that concerns government and/or
territory where the use of armed force between two parties, of which at least one is thegovernment of a state, results in at least 25 battle-related deaths.
Data on this category of organized violence is found in the UCDP/PRIO Armed Conflict Dataset(presently covering 1946-2020), in the UCDP Dyadic Dataset (1946-2020), in the UCDP Georeferenced Events Dataset (1989-2020), and in the UCDP Battle-related deaths Dataset (19892020). For more information, see the codebooks for these datasets, at
https://ucdp.uu.se/downloads/).

One-sided violenceOne-sided violence is defined as the use of armed force by the government of a state or by aformally organized group against civilians, which results in at least 25 deaths. Extrajudicial killings incustody are excluded.
Data on this category of organized violence is found in the UCDP One-sided Violence Dataset(1989-2020), and in the UCDP Geo-referenced Events Dataset (1989-2020). For more
information, see the codebook for the dataset, at https://ucdp.uu.se/downloads/).

Non-state conflict
A non-state conflict is defined as the use of armed force between two organized armed groups,
neither of which is the government of a state, which results in at least 25 battle-related deaths in ayear.
Data on this category of organized violence is found in the UCDP Non-state Conflict Dataset(1989-2020), and in the UCDP Geo-referenced Events Dataset (1989-2020). For more
information, see the codebook for the dataset, at https://ucdp.uu.se/downloads/).

Definition of a state actor
A state actor is always the government of a state.
A state is an internationally recognized sovereign government controlling a specific territory or aninternationally unrecognized government controlling a specified territory whose sovereignty is not
disputed by another internationally recognized sovereign government previously controlling thesame territory.
When in doubt as to who is actually controlling the government of a state, the party controlling thecapital of the state is regarded as the government.
In order to define the total population of states we use the Gleditsch & Ward (1999) systems
membership definition, which is based on the Correlates of War project. Gleditsch & Ward include
countries with a population of more than 250,000 that have ‘a relatively autonomous administration
over some territory’, and is ‘considered a distinct entity by local actors or the state it is dependenton’ (Gleditsch & Ward, 1999: 398).
The Gleditsch & Ward definition differs from our original definition in two main ways. First, for
Gleditsch & Ward a state is considered to be a new entity if it is ‘considered a distinct entity by local
actors’ while the conflict definition only recognizes it as a new entity when the ‘sovereignty is not
disputed by another internationally recognized sovereign government previously controlling thesame territory’. Second, the Gleditsch & Ward states all have a population of more than 250,000
while our conflict definition does not prescribe a specific size of the population. In a few cases,
countries with less than 250,000 inhabitants experience conflict or are active as secondary parties ina conflict. In those cases we use the Gleditsch & Ward tentative list of microstates. For example, themicrostate Tonga was part of the multinational coalition fighting in Iraq in 2004.
The UCDP/PRIO Armed Conflict Dataset includes one political entity that lacks a country code as
it is excluded from both the Gleditsch & Ward system membership table and the tentative list of
microstates: Hyderabad (Hyderabad vs. CPI and Hyderabad vs. India). In 1947 when England
granted India independence, a cabinet memorandum declared that the Princely States were free todecide to either join India or Pakistan before August 1947 - or devise their own sovereign politicalsystem for self-governance. Hyderabad declared itself independent on 15 August 1947. The state
was populated by approximately 15,000,000 inhabitants. The system membership ended when
Hyderabad was annexed by India in September 1948, after Winston Churchill had proposed to theUnited Nations to consider it as an independent state. GWNoA is set at 751.
In a few cases, the dataset have a different sovereignty date for some countries that haveexperienced conflict:
Armenia:
Gleditsch & Ward: 23 September 1991 (becomes independent)
UCDP/PRIO: 21 December 1991 (USSR formally ceased to exist)
Comment: On 23 September Armenia declares independence, but there is no indication that the
USSR ceased to lay claim to the territory at that time.
Azerbaijan:
Gleditsch & Ward: 30 August 1991 (becomes independent)
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UCDP/PRIO: 21 December 1991 (USSR formally ceased to exist)
Comment: While Gledistch & Ward state that Azerbaijan gained independence on 30 August 1991,
there is no indication that the USSR actually ceased to lay claim to the territory at that time.
Bosnia-Herzegovina:
Gleditsch & Ward: 3 Mars 1992 (declares independence)
UCDP/PRIO: 27 April 1992 (the new constitution of Yugoslavia)
Croatia:
Gleditsch & Ward: 25 June 1991 (declares independence)
UCDP/PRIO: 27 April 1992 (the new constitution of Yugoslavia)
Georgia:
Gleditsch & Ward: 6 September 1991 (the USSR’s recognition of Georgia’s declaration of
independence, on 9 April 1991)
UCDP/PRIO 21 December 1991 (USSR formally ceased to exist)
Comment: While Gleditsch & Ward claim that the USSR recognised Georgia’s independence on 6
September, this seems to be incorrect. On 6 September the Soviet Union recognized the Baltic
States’ independence, but not Georgia’s. Instead, the Soviet Union in early September 1991 refused
to discuss recognition of the declaration of independence.

Definition of a non-state actor
The UCDP Actor Dataset contains information on all actors/ groups/organisations that appear in
UCDP’s three categories of organized violence. Both the terminology and the type of organisations
included in the three categories vary to some degree. The UCDP/PRIO Armed Conflict Dataset
and the UCDP Dyadic Dataset includes “opposition actors” and “opposition organisations”, defined
as any non-governmental group of people having announced a name for their group and using
armed force to influence the outcome of the stated incompatibility. The UCDP One-sided Violence
Dataset contains “formally organized groups”, similarly defined, apart from the requirement of an
incompatibility. Lastly, the Non-state Conflict category in the UCDP Actor Dataset includes both“formally organized groups” and “informally organized groups”. While the former is the same
category as the one used in the One-sided Violence data, the latter is defined as any group without
an announced name, but who uses armed force against another similarly organized group. To be
included there has to be a clear pattern of violent incidents that are connected and in which bothgroups use armed force against the other.
The informally organized group are divided into two categories, members/supporters of politicalparties; and broader categories of identifications, such as ethnic groups and clans or religious groups.
The formally organized group category encompasses actors such as unrecognized states and rebel
groups.
As outlined above, the UCDP Actor Dataset thus contains information on a broad spectrum of nonstate actors. The smallest common denominators are that the non-state actor is an entity comprisedof several individuals and that it has some form of organisational structure (be it formal, as in e.g. rebel
groups or more traditional, as in e.g. ethnic groupings). Non-state actors included in the dataset hence
5range from small, informal ones such as the Dizi ethnic group in Ethiopia, numbering some 20 000
individuals, to large, state-like formations such as the self-declared Republic of Croatia (before it wasrecognised as an independent state).

Rules guiding the differentiation between non-state actors
To differentiate between non-state actors is at times problematic. 1 When is a non-state actor
completely new and when is it simply a continuation of an already registered non-state actor, only
slightly altered? Some actors tend to be fractious, splitting into different sub-groups while others joinlarger coalitions or umbrella groups. UCDP follows four main rules:






1

However many times a group changes its name, it retains the same Actor ID (for exceptions,see below).
When an actor splits into two or more actors, the splinter group/groups is considered acompletely new non-state actor.
Comment: It is sometimes difficult to determine which of the actors should be viewed as the
splinter and which should be seen as the original one, as both factions tend to claim to be the“original” actor. This is most typically the case concerning rebel groups. UCDP deals with thisby tracing the main part (i.e. the most numerous) of the actor, which is then coded as theoriginal one. Should this be problematic to determine, a second option is to trace the original
leader of the non-state actor in order to identify which actor to code as the original one.
When two or more already registered non-state actors join together under a new name in atight coalition with joint military operations, the new alliance is regarded as a new actor.
When an already registered non-state actor is joined by another actor that has previously not
been coded as active in the dataset, the new alliance is simply viewed as a continuation of theformer, previously coded, actor. This applies even when the name of the actor is changed.
Comment: It should be noted that while this rule is applied in most cases in the datasets
conventional logic made it necessary to make some exceptions. Whereas the rule works wellin e.g. the case of NRA in Uganda, which was originally called PRA but changed its name when
it was joined by the much smaller and militarily insignificant UFF, the logic is less clear in thecase of e.g. the Independent Nasserist Organisation in Lebanon (a.k.a. al- Mourabitoun), which
was active in fighting the government of Lebanon in 1958 and also resurfaced as part of the
Lebanese National Movement in 1975. In this case it is intuitively and factually incorrect tocharacterise the LNM as being a simple continuation of al- Mourabitoun, and the actor is thus
characterised as being an entirely new one.

This problem is mainly associated with the formally organized non-state actors.

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Variables in the Actor Dataset
Variable nameContent

Type

ActorId

The unique identifier of all actors

Integer

NameData

The name that is used for the actor in a UCDP dataset. String
The name used for an actor in UCDP data is either its
current one or the last name it had when registered in a
UCDP dataset. For formally organized non-state actors,
such as militias or rebel groups, the names listed in thisfield are by default acronyms when applicable.

NameOrig

The name of the actor when it was first included in a String
UCDP dataset.

NameOrigFull

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

StringNameOrigFullEng

The full original name of the actor, in English

StringNameChange

A binary variable that codes whether the actor has Boleanchanged its name. If the actor has changed its name, thisvariable is coded as 1. If not, a 0 is coded.

NewNameThe new name of the actor

String

NewNameFullMotherTongue

The full new name in mother tongue

String

NewNameFullEng

The full new name in English

String

Org

This variable indicates the organizational level of the actor. Integer
The level of organization is determined according to thefollowing categories:
Organizational level 1 (formally organized groups):
Rebel groups and other organized groups that have a highenough level of organization so as to be possible to include
in the state-based armed conflict category. These include
rebel groups with an announced name, as well as military
factions (Forces of…).
Organizational level 2 (informally organized groups):
Groups composed of supporters and affiliates to politicalparties and candidates. These are commonly not groups
that are permanently organized for combat, but who attimes use their organizational structures for such
purposes. In addition to supporters of political parties andcandidates, included in this category is also fighting
between groups composed of supporters of otherorganizations such as the supporters of al-Ahly footballteam fighting against the supporters of al-Masry footballteam in Egypt 2012.

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Organizational level 3 (informally organized groups):
Groups that share a common identification along ethnic,clan, religious, national or tribal lines. These are not groups
that are permanently organized for combat, but who attimes organize themselves along said lines to engage infighting.
Organizational level 4 (states):
The actor is the government of a state
ConflictId

The unique identifier of all state-based armed conflicts (i.e. String
conflicts included in the UCDP/PRIO Armed Conflict
Dataset) in which the actor has been recorded.
Comma-separated if multiple

DyadIdThe unique identifier of all dyads active in state-based String
armed conflicts (i.e. dyads included in the UCDP Dyadic
Dataset) in which the actor has been recorded.
Comma-separated if multiple

PrimaryParty

A binary variable that codes whether the actor has been a Bolean
primary party in a state-based armed conflict. If the actor
has been a primary party, this variable is coded as 1. If not,a 0 is coded.
This variable relates solely to actors active in state-based
armed conflicts.

OSID

The unique identifier of all dyads listed in the UCDP One- Integer
sided Violence Dataset.

OSCoalition

A binary variable listing whether the actor has been active Bolean
in one-sided violence together with one or several otheractors in the dataset. If the actor has been part of atemporary coalition in one-sided violence, this variable iscoded as 1. If not, a 0 is coded.

OSCoalitionID

The unique identifier of all temporary coalitions listed in String
the UCDP One-sided Violence Dataset.
Comma-separated if multiple

NSID

The unique identifier of all non-state dyads (i.e. nonconflicts included in the UCDP Non-state Conflict
Dataset) in which the actor has been recorded.

StringComma-separated if multiple
NSCoalition

8

A binary variable listing whether the actor has been active Bolean
in non-state conflict together with one or several otheractors in the dataset. If the actor has been part of a

temporary coalition in non-state conflict, this variable iscoded as 1. If not, a 0 is coded.
NSCoalitionID

The unique identifier of all temporary coalitions listed in String
the UCDP Non-state Conflict Dataset.
Comma-separated if multiple

SplinterA binary variable listing whether a non-state actor was Bolean
created by breaking away from another actor listed in
UCDP data.

NamePrev

Name of the actor that a given non-state actor broke away String
fromActorIdPrev

The unique identifier of the actor that a given group broke Integer
away from

SplitTemp

A binary variable listing whether a non-state actor was Bolean
created by a temporary split in the original movement.
Unlike the actors coded as created in the variable Splinter,
those formed in SplitTemp are of a temporary nature.
Often they may still view themselves as being part of theoriginal group, but divisions within it has caused fighting
between different factions or groupings. An example ofthis is fighting within the Taleban movement in
Afghanistan. In 1996, two Taleban commanders and theirfollowers fought each other over control of territory. The
two factions, Taleban - Ali Dad faction and Taleban - Mola
Khel faction, are registered in the UCDP Actor Dataset as
separate actors created from a temporary split from the
Taleban. The split is considered temporary as thecommanders, after the fighting had ceased, continued tobe part of the Taleban movement.

NameSplitTemp

Name of the actor that a given non-state actor String
temporarily broke away from

ActorIdSplitTemp

The unique identifier of the actor that a given group Integer
temporarily broke away from

Alliance

A binary variable listing whether a non-state actor entered Bolean
into an alliance with another non-state actor, also
registered in UCDP data, thus creating a new non-state
actor

NameAlliance

Name of the alliance created by the merger of two or String
more non-state actors

ActorIdAlliance

The unique actor identifier of the new non-state actor Integer(alliance) created by the merger of two or more non-state
actors9

JoinGroupA binary variable listing whether a non-state actor joined Bolean
a group already registered in UCDP data.
While this variable is closely related to the Alliancevariable, there is a fundamental difference between the
two. When an actor is coded in Alliance, it ceases to exist
on its own, as it together with another registered actor
creates a new organisation.
When an actor is coded in Join_group on the other hand,it ceases to exist because it joins, or is overtaken byanother already existing group. An example of this is thecase of the two Congolese rebel groups Ninjas andNtsiloulous. When the Cobra militia, together with
Angolan support, managed to oust the sitting president
Pascal Lissouba (supported by the Cocoyes) and his Prime
Minister Bernard Koleleas (supported by the Ninjas), theNinjas hid and regrouped in the Pool region. In a paralleldevelopment, a new group surfaced in Pool; theNtsiloulous. The Ntsiloulou leader Pasteur Ntumi wasable to attract a large following amongst the Ninjas who
thought that by following Ntoumi's orders they werecarrying out the will of God, and subsequently began
increasing his military force. Over time more and more
Ninjas joined the Ntsiloulous – some by their own free will
and others under the threat of force – until, eventually, theNinjas had ceased to exist.

GroupName

Name of the non-state group that the given non-state String
actor joined

ActorIdGroupThe unique actor identifier of the group that a given non- Integer
state actor joined

Location

The countries in which the actor has been active.

StringComma-separated if multiple
GWNOLoc

The Gleditsch and Ward code for the countries in which String
the actor has been active.
Comma-separated if multiple

RegionIdentifies the region of the location
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).

String

VersionThe version of the dataset: 21.1

Float

10

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 21.1 of the UCDP Actor Dataset. We recommend thatwhenever this dataset 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.

A note on UCDP ID changes
In version 17.1 of all UCDP datasets, the ID system for conflicts, actors and dyads was changed inorder to make them unique across all UCDP core datasets and all UCDP types of violence. 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 compatible
with 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 ID
systems.
A conversion table between the new and old ID systems is available here:
http://ucdp.uu.se/downloads/.

References
Gleditsch, Kristian S. & Michael D. Ward. 1999. "Interstate System Membership: A Revised List of
the Independent States since 1816." International Interactions 25: 393-413
Pettersson, Therese, Shawn Davis, Amber Deniz, Garoun Engström, Nanar Hawach, Stina
Högbladh, Margareta Sollenberg & Magnus Öberg (2021). Organized violence 1989-2020, with a
special emphasis on Syria. Journal of Peace Research 58(4): 809-825
11