Frequently Asked Questions

Can I use the GTD for my research/analysis/project?
Why does the data set end in 2012?
Why are the data for 1993 missing?
Why doesn't GTD have a single set definition of terrorism?
I came across an incident in the database that I do not believe is terrorism. Why was it included?
I found a factual error or a case missing from the database. How did this happen?
Does the GTD include foiled and failed plots or threats to attack?
Does the GTD include insurgency?
Does the GTD include incidents of state terrorism?
Who makes the decisions about what to include as an incident?
How do I get access to the raw data?
Who funds the database?
Is there a methodological reason for the decline in the data between 1997 and 1998, and the increases since 2008 and 2012?
I need to provide GTD data for a academic journal replication archive. Do I need permission?
Can the GTD be used as a source of information on legal dispositions of criminal charges?

 


Can I use the GTD for my research/analysis/project?

Yes, we encourage researchers, analysts, and scholars to use the GTD in their work. Users can download the latest dataset by filling out the brief GTD Contact Form and selecting “Download full GTD dataset” from the Action drop-down menu. Use of the data signifies your agreement to our Terms of Use, which include properly citing the GTD as a data source, and refraining from redistributing or republishing the raw data for commercial or non-commercial use.

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Why does the data set end in 2012?

GTD collection beyond 2012 is ongoing and the website is updated annually. We expect to release the 2013 data in Summer 2014. Please join START’s mailing list to be notified when the GTD is updated.

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Why are the data for 1993 missing?

The original PGIS data, upon which the 1970-1997 GTD data are based, consisted of hard-copy index cards, which were subsequently coded electronically by START researchers. Unfortunately, the set of cards for 1993 was lost prior to PGIS handing the data over to START. Country-level statistics for 1993, including number of incidents, number of fatalities, number injured, number of U.S. fatalities, and number of U.S. injured were recovered from a PGIS Risk Assessment Report for 1993. These figures are available in the appendix of the GTD Codebook.

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Why doesn't GTD have a single definition of terrorism?

In the absence of a universally accepted definition of terrorism, GTD uses several coded criteria to cover a broad range of definitions of terrorism through a combination of inclusiveness and filtering. The goal is to have a data set that is useful to as many interested users as possible.

Please see our Methodology Page and GTD Codebook for more details.

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I came across an incident in the database that I do not believe is terrorism. Why was it included?

While the GTD inclusion criteria offer a comprehensive definition of terrorism, we encourage users to take advantage of the GTD's flexibility to restrict the data according to their definitional preferences. This includes filtering search results based on whether the coder noted some uncertainty whether an incident meets all of the criteria for inclusion ("Doubt Terrorism Proper," available for post-1997 cases only). Also, users can filter search results based on which of the following three criteria are met (available for all cases):

Criterion I: The act must be aimed at attaining a political, economic, religious, or social goal.
Criterion II: There must be evidence of an intention to coerce, intimidate, or convey some other message to a larger audience (or audiences) than the immediate victims.
Criterion III: The action must be outside the context of legitimate warfare activities.

Please see our Methodology Page and GTD Codebook for more details.

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I found a factual error or a case missing from the database. How did this happen?

While every effort is made for each incident to corroborate facts from multiple independent sources and to eliminate errors through a systematic review process, the magnitude of the database (over 113,000 discrete incidents) means that occasionally an error will evade detection and appear in the database or a valid incident will not be recorded. In these cases, we rely on users who become aware of such an error to contact us and let us know.

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Does the GTD include foiled and failed plots or threats to attack?

Although the GTD does include failed attacks, it does not include foiled or failed plots, the distinction being that the attack must actually be attempted to qualify for inclusion in the database. Likewise, the GTD does include attacks in which violence is threatened as a means of coercion, but does not include threats to attack where no action is taken.

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Does the GTD include insurgency?

To some degree, the GTD does include acts that occur either during a specific insurgency or that closely resemble an insurgent attack against a military target. Without clear definitions of terrorism and insurgency in the literature these types of actions can overlap, with insurgent organizations using violence against non-combatants alongside attacks directed at combatants. While terrorism as a tactic has been used within a number of insurgent campaigns, the GTD should not be viewed as a comprehensive collection of insurgent attacks.

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Does the GTD include incidents of state terrorism?

No, the GTD is limited to acts of non-state terrorism. One of the three necessary criteria for inclusion is that there must be sub-national perpetrators.

Please see the GTD Codebook for more details.

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Who makes the decisions about what to include as an incident?

The basic criteria were formulated by the GTD Advisory Board, and were reflected in the data collection process. In practice, individual data collectors decide whether a case they are working on fulfills these criteria, and this decision is reviewed by GTD supervisory staff. In cases where determination is difficult, the decision is made by the senior GTD management. If uncertainty persists, exceptionally difficult cases can be referred to the GTD Advisory Board for discussion and adjudication.

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How do I get access to the raw data?

Users can download the latest dataset by filling out the brief GTD Contact Form and selecting “Download full GTD dataset” from the Action drop-down menu. United States government officials can request a copy of the GTD data files from the latest release on compact disc through the GTD Contact Form as well.

Please join the START mailing list to receive a notification when more recent versions of the data become available.

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Who funds the database?

The initial collection of GTD data was carried out by the Pinkerton Global Intelligence Services (PGIS) between 1970 and 1997 and was donated to Gary LaFree at the University of Maryland. Computerizing and validating the original GTD data from 1970 to 1997 was funded by a grant from the National Institute of Justice (PIs Gary LaFree and Laura Dugan; grant number: NIJ2002-DT-CX-0001) and thereafter as part of the START Center of Excellence by the Department of Homeland Security Science and Technology Directorate (DHS S&T), Office of University Programs (PI Gary LaFree; grants number N00140510629 and 2008-ST-061-ST0004). Data collection funding for GTD from 1998 to 2007 was supplied by the DHS S&T Human Factors Division (PIs Gary LaFree and Gary Ackerman; contract number HSHQDC-05-X-00482). All information in the database on events through 2007 was collected and coded by database staff at the National Consortium for the Study of Terrorism and Responses to Terrorism (START) and the Center for Terrorism and Intelligence Studies (CETIS).

Data on cases for 2008 through 2011 have been funded by a grant from the Office of University Programs, Science and Technology Directorate, U.S. Department of Homeland Security (PI Gary LaFree; grants number #2008-ST-061-ST0004). In addition, efforts to review and update information on terrorist incidents in the United States have been supported through funding from the Department of Homeland Security Science and Technology Directorate's Resilient Systems Division (PI Gary LaFree, grant number # 2009ST108LR0003). For GTD data collection from 2008 to November 2011, START partnered with the Institute for the Study of Violent Groups (ISVG), headquartered at New Haven University. Beginning in November 2011 the START Consortium headquartered at the University of Maryland began collecting the original data for the GTD. The collection of GTD data beginning in 2012 is collected by START and jointly funded by the U.S. Department of Homeland Security (PI Gary LaFree; grant # 2012-ST-061-CS0001) and by the U.S. State Department (PIs Gary LaFree and Erin Miller; contract # SAQMMA12M1292).

The GTD does not purport to represent the official position, inclusion decisions, or information holdings of the Department of Homeland Security, the National Institute of Justice, the U.S. State Department or any other funding agency.

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Is there a methodological reason for the decline in the data between 1997 and 1998, and the increases since 2008 and 2012?

While efforts have been made to assure the continuity of the data from 1970 to the present, users should keep in mind that the data collection was done as events occurred up to 1997, retrospectively between 1998 and 2007, and again concurrently with the events after 2008. This distinction is important because some media sources have since become unavailable, hampering efforts to collect a complete census of terrorist attacks between 1998 and 2007. Moreover, since moving the ongoing collection of the GTD to the University of Maryland in the Spring of 2012, START staff have made significant improvements to the methodology that is used to compile the database. These changes, which are described both in the GTD codebook and in this START Discussion Point on The Benefits and Drawbacks of Methodological Advancements in Data Collection and Coding: Insights from the Global Terrorism Database (GTD), have improved the comprehensiveness of the database. Thus, users should note that differences in levels of attacks before and after January 1, 1998, before and after April 1, 2008, and before and after January 1, 2012 may be at least partially explained by differences in data collection; and researchers should adjust for these differences when modeling the data.

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I need to provide GTD data for an academic journal replication archive. Do I need permission?

Yes. The Terms of Use for the GTD specifically prohibit the republication of the GTD data in any manner on any publicly-available website. This includes journal replication archives and institute / research center websites, among others. If an academic publication requires the posting of GTD data in the replication archive, please contact GTD staff to obtain permission to post the GTD data.

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Can the GTD be used as a source of information on legal dispositions of criminal charges?

No. Statistical information contained in the Global Terrorism Database is based on reports from a variety of open media sources. Information is not added to the GTD unless and until we have determined the sources are credible. Users should not infer any additional actions or results beyond what is presented in a GTD entry and specifically, users should not infer an individual associated with a particular incident was tried and convicted of terrorism or any other criminal offense. If new documentation about an event becomes available, an entry may be modified, as necessary and appropriate.

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