Frequently Asked Questions

Can I use the GTD for my research/analysis/project?
Why does the data set end in 2020?
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 GTD?
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. 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.

Why does the data set end in 2020?

GTD collection beyond 2020 is ongoing and the website is typically updated annually. Contingent on renewal of funding, we hope to release the 2021 data as soon as we are able. Please join START’s mailing list to be notified when the GTD is updated.

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.

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.

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," systematically 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.

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 (more than 200,000 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.

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.

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.

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.

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.

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.

Who funds the GTD?

All decisions about GTD data collection are made independently by the GTD research team. Any opinions, findings, or conclusions are those of the researchers and do not reflect the views or policies of any funding agency.

The initial collection of data was carried out by the Pinkerton Global Intelligence Services (PGIS) and included records of attacks that took place between 1970 and 1997. These handwritten records were donated to Gary LaFree at the University of Maryland in 2002
United States National Institute of Justice: NIJ funded the efforts to digitize the original data on events from 1970 to 1997 (PIs Gary LaFree and Laura Dugan; grant no. NIJ2002-DT-CX-0001)
United States Department of Homeland Security, Science and Technology Directorate (DHS S&T):
- As part of the National Consortium for the Study of Terrorism and Responses to Terrorism (START) Center of Excellence, data cleaning, organization, and analysis for the 1970 through 1997 records were supported by the DHS S&T Office of University Programs (PI Gary LaFree; grant no. N00140510629)
- Funding for records of attacks from 1998 to 2007 was supplied by the DHS S&T Human Factors Division (PIs Gary LaFree and Gary Ackerman; contract no. HSHQDC-05-X-00482). Data collection for events through March 2008 was conducted by research staff at START and the Center for Terrorism and Intelligence Studies (CETIS).
- Data on attack records for 2008 through 2011 were funded by a grant from the DHS S&T Office of University Programs (PI Gary LaFree; grant no. 2008-ST-061-ST0004). For GTD data collection on events from April 2008 to November 2011, START partnered with the Institute for the Study of Violent Groups (ISVG), headquartered at New Haven University.
- Collection, analysis, and transition of GTD data on attacks that took place from 2012 to 2017 was supported by the DHS S&T Office of University Programs (PI Gary LaFree; grant no. 2012-ST-061-CS0001)
- Efforts to review, update, and supplement information on terrorist attacks in the United States from 1970 through 2018 were supported by funding from the DHS S&T's Resilient Systems Division (PI Gary LaFree, grant no. 2009ST108LR0003) and DHS S&T's Enterprise and First Responders Group (PI Erin Miller contract no. 70RSAT18FR0000119).
United States Department of State, Bureau of Counterterrorism and Countering Violent Extremism: Beginning in November 2011 the GTD team headquartered at the University of Maryland designed new data collection tools and workflows, and began collecting all data for the GTD. Data collection for attacks that took place from 2012 to 2017 was supported by the Department of State to support the annual publication of the Country Reports on Terrorism Statistical Annex (PIs Gary LaFree and Erin Miller; contracts no. SAQMMA12M1292 and SAQMMA13F1447).
United States Department of Defense, Combating Terrorism Technical Support Office: CTTSO contributed funds to support the collection of data on attacks that took place in 2019, as well as making technological advancements to data collection processes as part of the Enhancing Datastreams to Inform Counter-Terrorism (EDICT) program (PI Erin Miller; contract no. W911NF19F0014)
German Federal Foreign Office: The FFO contributed funds to support the collection of data on attacks that took place between 2019 and 2021, as well as making technological advances to the data collection process, and a pilot study on real-time data collection. (PI Erin Miller; grants no. 19061669 and 21052581)
United Kingdom Foreign, Commonwealth, and Development Office: The FCDO contributed funds to support data collection for terrorist attacks that took place in 2020 and 2021 and to conduct a pilot study on documenting the nationality of victims of terrorist attacks (PI Erin Miller; grant no. 120365514 and 120384517)
United States Department of Defense, Basic Research Office: DOD Basic Research contributed funds to support data collection for attacks that took place in 2020 and 2021, as part of the Asymmetric Threats Analysis Center (ATAC) (PI Erin Miller; contract no. HQ003421F0481)

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.

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.

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.