Contact Us

We welcome questions and feedback from users. For the quickest answers, please consult the FAQs below to see if your question has already been addressed before submitting it using the form below.


Why has the licence for using GTD changed?

In order to secure the long term financial viability of the GTD™, we decided in 2019 that we woulld engage more pro-actively with the number of organizations who value the GTD™. By engaging with a commercial distribution partner, CHC Global, we have been able to guarantee that the GTD™ remains freely available for personal research, whilst engaging with organizations in a more appropriate way. The terms of use remain mostly unchanged, with only minor amends made to reflect the nature of our relationship with CHC Global. There should be no noticeable change to how individuals can use the GTD™ for personal research purposes.

What should I do if I’m unsure whether I meet the individual use definition?

If you’re unsure if you or the organization you represent meet the definition for individual use, please complete the contact form for organizational use and explain your situation in the comments box. We will be in touch to discuss your question.

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 following the links on the “Access the GTD” pages for “Individual Use”. You will be required to accept the End User Agreement. It is vital that you cite the GTD™ appropriately, acknowledge any changes you make to the GTD™ in your analysis, and carefully read the End User Agreement as there are important restrictions to ensure that the data is only used for the purpose of better understanding, or defeating terrorism.

How can US Government employees and contractors download the GTD?

Because the United States Government (USG) partially funded the collection of the GTD, USG users have "Government Purpose" rights in the existing data. To access the GTD, USG users can select "Organizational Use" and fill out the brief form to request access. Our distribution partner, CHC Global will confirm access within two business days. Non-government organizations interested in using the GTD for USG purposes should request access through their USG client. Non-government organizations interested in using the GTD for non-USG purposes should select "Organizational Use," and fill out the brief form to request access. CHC Global will respond with additional information about licensing within two business days.

Can I still search and browse the data without downloading the file?

Yes. All users can search and browse the database as long as they accept the individual terms of use.

Why is there a delay in releasing the data?

GTD source document collection occurs daily, and systematic curation of structured data takes place on a 3-4 month lag behind “real time.” The process of open source collection and then refining and checking each entry takes our researchers time. The database is typically updated annually for non-commercial users. Commercial users have access to preliminary data updates on a more frequent basis, usually quarterly. The GTD is produced with the intent of providing a long term view of terrorism and as such, we prioritize accuracy and completeness.

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 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 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 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 180,000 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.

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.

Who funds the database?

In the past, GTD™ collection, maintenance, and improvements have been funded by:

  • United States National Institute of Justice
  • United States Department of Homeland Security, Science and Technology Directorate
  • United States Department of State, Bureau of Counterterrorism and Countering Violent Extremism

Currently, GTD™ collection, maintenance, and improvements are funded by:

  • United States Department of Defense, Combatting Terrorism Technical Support Office
  • German Federal Foreign Office

All decisions about GTD data collection are made independently by the research team. The GTD does not represent the official position of any funding agency.

Get in Touch

Please select the team you would like to get in touch with from the list below:

GTD Media Enquiries

For general media inquiries or insight from START researchers, contact START’s Communications Director here.

GTD Analyst Team

For questions or feedback about the GTD, the data collection process, and analysis contact the GTD team at START here.

Licensing Enquiries

For questions about commercial and non-commercial GTD licensing or consultation with GTD researchers, contact CHC Global here.


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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