Rüdiger Voigt | last update: 2016-11-01
Besides a qualitative approach quantitative methods have merits to further the scientific understanding of terrorism. They allow it to check theories on group behavior like outbidding logic (i.e. the response of a terrorist group on the appearance of a competing group). More importantly it makes it possible to estimate the effect of anti-terror policies on the operational abilities of the targeted groups.
The Global Terrorism Database (GTD) is the by far largest public data collection of terrorist attacks. It holds information on more than 150,000 incidents between 1970 and 2015. Updates are sporadic, even though the publisher plans to update the database once a year. The web interface allows basic interaction with the data, but the database itself is available to researchers as a Microsoft Excel-file.
The GTD is maintained by the National Consortium for the Study of Terrorism and Responses to Terrorism (START). Since 2012 START contracted with the U.S. Department of State to collect a Statistical Annex for the Country Reports on Terrorism (formerly "Patterns of Global Terrorism") which are released annually since the year 2000.
The only public database comparable to the GTD was the Worldwide Incidents Tracking System (WITS). Yet the U.S. government cut funding of the public version and those data are not available anymore. A direct comparison with the GTD showed that WITS contained more information for some time periods, but less for others. This may have been due to different definitions of what qualifies, or different assessments of the credibility of media reports on alleged acts of terrorism. Most importantly it showed that the GTD is not perfect, but due to loss of WITS it is not possible to compare trends or observations on a larger scale.
There are some smaller projects like the RAND Database of Worldwide Terrorism Incidents (RDWTI). As of November 2016, it contained more than 36,000 incidents from 1972 to 2009. RAND calls it "the gold standard for comprehensive information on international and domestic terrorism". Though a quick search on acts of terrorism in Germany revealed that the database has no entries for dozens of larger incidents in the 1970s.
Another interesting scientific project is the Suicide Attack Database maintained by the Chicago Project on Security and Terrorism.
For the purpose of export control nearly all governments publish records on Foreign Terrorist Organizations. For example, there is the U.S. State Department’s database or the E.U. list of persons, groups and entities involved in terrorist acts and subject to restrictive measures. Even the United Nations publish an ISIL (Da'esh) & Al-Qaida Sanctions List. The FBI has a Most Wanted Terrorists list.
There are several classified databases like the U.S. government’s Terrorist Identities Datamart Environment (TIDE). In Germany there are the Anti-Terror-Datei for international terrorism and the Rechtsextremismusdatei (RED) which tracks right wing extremists.
There are still some commercial database such as those provided by the Intel Center, the International Terrorism: Attributes of Terrorist Events (ITERATE) database or Data on Terrorist Suspects (DOTS).