Cross-National Patterns of Terrorism: Comparing Trajectories for Total, Attributed and Fatal Attacks, 1970-2006

Despite growing international concern about terrorism, until recently, very little was known about worldwide risk patterns for terrorist attacks. In this paper, we are especially interested in determining the extent to which terrorism is concentrated at the country level over time and whether different measures of terrorism (total, attributed and fatal attacks) yield similar results. Traditional sources of crime data—official police records and victimization and self-report crime surveys—typically exclude terrorism. In response, there has been growing interest in terrorist event databases. In this research, we report on the most comprehensive of these databases to date, formed by merging the Global Terrorism Database maintained by the START Center with the RAND-MIPT database. We use a statistical method called semi-parametric group-based trajectory analysis to examine 73,961 attacks in 206 countries and territories from 1970 to 2006. Our results confirm that terrorist attacks, like more common crimes, are highly concentrated across specific countries and these concentrations are fairly stable over time. Ten countries account for 38 per cent of all terrorist attacks in our data since 1970; 32 countries account for more than three-quarters of all attacks. The trajectory analysis also reveals a rapidly rising new terrorist threat concentrated especially among countries in South and Southeast Asia, the Middle East and Africa.