Aaron Clauset, Kristian Gleditsch

Paper #: 09-07-021

Traditional studies of terrorist group behavior focus on questions of political motivation, strategic choices, organizational structure, and material support, but say little about the basic laws that govern how the frequency and severity (number of deaths) of their attacks change over time. Here we study 3,143 fatal attacks carried out worldwide from 1968--2008 by 381 terrorist groups, and show that the frequency of a group's attacks accelerates along a universal trajectory, in which the time between attacks decreases according to a power law in the group's total experience; in contrast, attack severity is independent of organizational experience and organizational size. We show that the acceleration can be explained by organizational growth, and suggest that terrorist organizations may be best understood as firms whose primary product is political violence. These results are independent of many commonly studied social and political factors, suggesting a fundamental law for the dynamics of terrorism and a new approach to understanding political conflicts.