A Department of Homeland Security Center of Excellence led by the University of Maryland

Global Terrorism Database (GTD)

Global Terrorism Database (GTD)

Project Details


The Global Terrorism Database (GTD) includes information on more than 150,000 terrorist attacks that occurred worldwide between 1970 and 2015. The global scope of the GTD across four decades allows analysts to explore terrorism trends in numerous contexts.

Data Validation: (1) review and systematic comparison with additional open-source materials, including trial transcripts, secondary source materials like specialized monographs, specialized databases such as those maintained by the United Nations and in-person interviews with experts and practitioners; and (2) enhanced role of GTD Advisory Board for vetting and reviewing case classifications

Data Availability: Ongoing enhancement of GTD online interface and development of web-based analytical tools

Data Analysis: Building on past work involving the GTD, researchers will continue to apply advanced statistical methods for identifying important trends and patterns related to radicalization, terrorist operations, counter-terrorism, and the impact of terrorism.

Primary Findings: 

Some general findings derived from the GTD involve the nature and distribution of terrorist attacks. For example, over half of all terrorist attacks in the GTD are non-lethal, and approximately two percent involve 20 or more fatalities. The events in the GTD are attributed to over 2,000 named perpetrator organizations and nearly 700 additional generic groupings such as "Tamil separatists." However, over 70 percent of these groups are active for less than a year and carry out fewer than four total attacks. Likewise, only 20 perpetrator groups are responsible for over 50 percent of all attacks from 1970 to 2010 for which a perpetrator is identified.

START researchers use the GTD to conduct statistical analyses of patterns of terrorist attacks, perpetrator groups, and responses to terrorism using innovative analytical strategies. Select findings from these analyses include: (1) the vast majority of terrorist attacks, including those attributed to organizations that represent the most serious foreign threat to the US, mostly attack domestic targets in their own countries; (2) conciliatory actions by the Israeli government are sometimes more effective at reducing terrorist attacks than are repressive actions, especially during the Second Intifada; (3) perpetrator organizations can be classified into those that desist rapidly and those that desist gradually, if at all, based on the shape of their activity over time; and (4) the groups most likely to persist are those with a rapid pattern of onset, while those with a gradual pattern of onset are more likely to decline quickly.


The GTD team completed the collection of data on terrorist attacks worldwide through 2015 by systematically reviewing thousands of unclassified source documents to identify intentional acts of violence by non-state actors that satisfy at least two of the following three inclusion criteria:

1. The violent act was aimed at attaining a political, economic, religious, or social goal;

2. The violent act included evidence of an intention to coerce, intimidate, or convey some other message to a larger audience (or audiences) other than the immediate victims; and

3. The violent act was outside the precepts of International Humanitarian Law.

For each qualifying event, the database includes specific information on up to 120 separate attributes regarding when and where the attack occurred, the perpetrators and victims involved, tactics and weapons used, and the outcome of the attack. During this period of performance the GTD team completed the synthesis of the original 1970-1997 ("GTD1") data and newly collected post-1998 data in order to form a single file of consistently coded information. The GTD team also completed numerous supplemental data collection projects across a variety of domains spanning the entire time series in an ongoing effort to ensure comprehensive coverage.


Project Period: 
June 2008 to June 2018

Selected Publications

Terrorism in Mali (Fact Sheet)
Overview: Terrorism in 2014 (Background Report)
Boko Haram Recent Attacks (Background Report)

News References

Dawn: Attacks on schools (START in the News)
Scripps: Terrorism in Turkey (START in the News)
DAWN: Education for Fata (START in the News)
2014 GTD data available now (Featured Research)
Washington Times: (START in the News)
Violent extremism in the U.S. (Featured Research)
CBRNIAC Newsletter: (START in the News)
CQPolitics: (START in the News)
CQ Homeland Security: (START in the News)