Introducing Extended Data on Terrorist Groups (EDTG), 1970 to 2016

• Published date: 01 January 2020
• DOI: 10.1177/0022002719857145
• Author: Khusrav Gaibulloev,Dongfang Hou,Todd Sandler
• Date: 01 January 2020
• Subject Matter: Data Set Feature

Data Set Feature

Introducing Extended

Data on Terrorist Groups

(EDTG), 1970 to 2016

Dongfang Hou

1

, Khusrav Gaibulloev

2

, and Todd Sandler

3

Abstract

This article introduces an extended data set of 760 terrorist groups that engaged in

attacks during 1970 to 2016. Unlike most extant group data sets, the extended data

on terrorist groups (EDTG) is not tied to terrorist groups and attacks listed in the

RAND terrorism data; rather, EDTG is linked to terrorist groups and attacks given

in the Global Terrorism Database. Terrorist groups’ variables in EDTG include

ideology, main goals, start date, duration, base country, attack diversity, peak size,

alternative endings (if relevant), and others. We display interesting features of EDTG

through a series of tables and figures. Our EDTG-based survival analysis is at odds

with some of the literature: for example, the demise of a leader and a larger share of

transnational terrorist attacks increase the group’s odds of failure. After 2001,

religious terrorist groups are more resilient than those with other ideologies. We

also analyze terrorist group lethality and productivity.

Keywords

extended data on terrorist groups, Global Terrorism Database, domestic and

transnational terrorist attacks , terrorists’ ideologies and goals , terrorist groups’

survival

1

School of Applied Economics, Renmin University of China, Beijing, China

2

Department of Economics, American University of Sharjah, Sharjah, UAE

3

Department of Economics, School of Economic, Political & Policy Sciences, University of Texas at Dallas,

Dallas, TX, USA

Corresponding Author:

Todd Sandler, School of Economic, Political and Policy Sciences, University of Texas at Dallas, 800 W.

Campbell Road, Richardson, TX 75080, USA.

Email: tsandler@utdallas.edu

Journal of Conflict Resolution

2020, Vol. 64(1) 199-225

ªThe Author(s) 2019

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DOI: 10.1177/0022002719857145

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Why is extended data on terrorist groups (EDTG) so essential? To understand

terrorism and its drivers, researchers must investigate terrorist groups’ characteris-

tics and actions that create casualties, achieve demands, determine base location, and

affect their longevity. Knowledge of those things can foster more effective counter-

terrorism measures to limit terrorist groups’ carnage, political consequences, and

economic ramifications. If measures can be devised to disrupt sufficiently the oper-

ation of terrorist groups, then those countermeasures can limit the associated terror-

ist campaigns. Terrorist groups solicit support from the base country population,

other terrorist groups, and state sponsors so that the impact of such s upport on

groups’ viability must be ascertained. To assess properly terrorist groups’ actions

and prowess, research must have an up-to-date data set on terrorist groups which

contains their start date, duration, goals, ideology, location, size, lethality, strategic

decisions, leadership structure, and other characteristics. That data set must be

bolstered by observations from other data sources, such as the World Bank’s

(2018) World Development Indicators (WDI), to include economic and demo-

graphic variables from the terrorist groups’ base countries.

Terrorist groups may last for one or a few attacks, or they may exist for over fifty

years (Blomberg, Engel, and Sawyer 2010; Phillips 2017). What affects terrorist

groups’ survival? That survival may hinge on strategic considerations of the terrorist

groups, countermeasures of governments, sponsorship from a government, or sup-

port from allied terrorist groups. The pioneering article on the determinants of

terrorist group longevity is by Blomberg, Engel, and Sawyer (2010) who apply a

survival or time-to-failure model. Subsequent studies on terrorist groups’ survival

include Blomberg, Gaibulloev, and Sandler (2011), Carter (2012), Gaibulloev and

Sandler (2013, 2014), Phillips (2014, 2017), and others. In three earlier landmark

contributions, Cronin (2006, 2009) and Jones and Libicki (2008) discuss factors

behind terrorist group demise but do not employ survival models. Those three

studies emphasize the importance of groups’ size, their ideology, and alternative

endings (e.g., having demands met, being annihilated, joining the political system, or

splintering). Cronin (2006, 2009) makes clear that the death or capture of a terrorist

group’s leader, even a charismatic one, need not end the group, as the assassination

of Osama bin Laden in May 2011 later demonstrated (also see Jordan 2009). Other

studies on terrorist groups investigate the determinants of their lethality (Asal and

Rethemeyer 2008; Horowitz and Potter 2014), the diffusion of innovations (Horo-

witz 2010), the factors behind location decisions (Gaibulloev 2015), or the impact of

state sponsorship (Carter 2012).

With the collection of terrorist event data sets, information was accumulated on

terrorist groups that were thought responsible for terrorist attacks after 1967. The

three most important event data sets—International Terrorism: Attributes of Ter-

rorist Events (ITERATE; Mickolus et al. 2018), Global Terrorism Database (GTD;

National Consortium for the Study of Terrorism and Response to Terrorism

[START] 2018), and RAND Database of Worldwide Terrorism Incidents (RAND

2012)—provide key variables that can be linked to terrorist groups over time. Those

200 Journal of Conflict Resolution 64(1)