About the GTD

Managed by the National Consortium for the Study of Terrorism and Responses to Terrorism (START), the Global Terrorism Database™ includes more than 190,000 terrorist attacks dating back to 1970. Read about the history of the GTD™ below.

Overview

The Global Terrorism Database (GTD) is an open-source database including information on domestic and international terrorist attacks around the world from 1970 through 2018, and now includes more than 190,000 cases. For each event, information is available on the date and location of the incident, the weapons used and nature of the target, the number of casualties, and–when identifiable–the group or individual responsible.

The National Consortium for the Study of Terrorism and Responses to Terrorism (START) makes the GTD available via this online interface in an effort to increase understanding of terrorist violence so that it can be more readily studied and defeated.

Characteristics of the GTD

  • Contains information on over 190,000 terrorist attacks
  • Currently the most comprehensive unclassified database on terrorist attacks in the world
  • Includes information on more than 91,000 bombings, 20,000 assassinations, and 13,000 kidnappings and hostage events since 1970
  • Includes information on at least 45 variables for each case, with more recent incidents including information on more than 120 variables
  • More than 4,000,000 news articles and 25,000 news sources were reviewed to collect incident data from 1998 to 2018 alone

History of the GTD

The Global Terrorism Database began in 2001 when the Pinkerton Global Intelligence Services (PGIS) donated an archive of handwritten records to researchers at the University of Maryland. From 1970 to 1997, PGIS trained researchers–mostly retired Air Force personnel–to identify and record information about terrorist attacks from wire services, government reports, and major international newspapers in order to assess the risk of terrorism for their clients. The University of Maryland research team finished digitizing the original Pinkerton data in December 2005, making corrections and adding additional information wherever possible. PGIS lost data for 1993 in an office move and these data have never been fully recovered.

In April 2006, the newly formed National Consortium for the Study of Terrorism and Responses to Terrorism (START), working with the Center for Terrorism and Intelligence Studies (CETIS), began the process of extending the GTD beyond 1997. This included expanding the types of data collected, and parsing the PGIS definition of terrorism into a set of distinct inclusion criteria, which the research team at START then retroactively applied to all events back to 1970. The CETIS team ultimately recorded information on attacks that took place from January 1998 through March 2008. They also endeavored to re-collect the missing 1993 data. This effort was unfortunately unsuccessful, in part due to the fact that source documents from that period were not sufficiently preserved.

In April 2008, analysts from the Institute for the Study of Violent Groups (ISVG) at the University of New Haven began collecting data for inclusion in the GTD. ISVG’s collection effort, which continued through March 2012, included data on terrorist attacks that occurred between April 2008 and October 2011. GTD researchers at START integrated these data into the GTD, and continued to routinely review a wide array of sources to identify additional cases and additional information about previously identified cases back to 1970 to help ensure that GTD is as comprehensive and accurate as possible.

Beginning with attacks that occurred in November 2011, all ongoing GTD data collection efforts are conducted by START researchers at the University of Maryland.

Data Collection Methodology

 

Since moving the ongoing collection of the GTD to the University of Maryland in April 2012, the GTD team has made significant improvements to the methodology used to compile the database, balancing the strengths of artificial and human intelligence. The process begins with a more diverse set of news media sources from around the world for identifying and documenting the incidents that are included in the GTD—more than two million articles published daily. Natural language processing, named entity extraction, and machine learning models facilitate the identification and organization of news articles that include information about terrorist attacks. The GTD team developed a proprietary Data Management System that allows analysts to identify unique attacks, record the details of each event, and update records for previously recorded events as new information becomes available.

Key factors that impact the content of datasets like the GTD include definitions, sources, and workflows. While the GTD team has applied a single definition of terrorism over the full span of the database, access to source materials and the efficiency of workflows have varied over time. For example, the availability of source materials was best at times when the data collection had the shortest lag behind real time. Improvements in technology and the expansion of the internet have enhanced both the accessibility of source materials and the efficiency of workflows. In general, users should interpret trends over time with caution. In particular, note that differences in levels of attacks and casualties before and after January 1, 1998; April 1, 2008; and January 1, 2012 may be partially explained by shifts in data collection. Likewise, the GTD is not directly comparable to other sources of data on terrorism, as differences in definitions, sources, and workflows will produce misleading inferences.

For detailed documentation of the data collection methodology, please consult the GTD Codebook.

To search and browse the GTD, click on the button below:

The GTD Team

Senior Researchers
  • Erin Miller, Principal Investigator
  • Michael Jensen, Data Collection Manager
  • Brian Wingenroth, Software Architect
Researchers
  • Bryan Arva
  • Michael Distler
  • Benjamin Evans
  • Sheehan Kane
  • Jacob Loewner
  • Joseph Oudin
  • Karina Panyan
GTD Advisors

Founding Principal Investigators

  • Laura Dugan, University of Maryland
  • Gary LaFree, University of Maryland
GTD Advisory Board
  • Victor Asal, SUNY Albany
  • Martha Crenshaw, Stanford University
  • Joshua Freilich, John Jay College of Criminal Justice
  • Clark McCauley, Bryn Mawr College
  • Todd Sandler, University of Texas, Dallas
  • Jacob Shapiro, Princeton University
  • John Wigle, Harvard University
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National Consortium for the Study of Terrorism and Responses to Terrorism
An Emeritus Center of Excellence of the U.S. Department of Homeland Security