This chapter explores the average longevity, characteristics, and operational environment of terrorist groups. A large number of terrorist groups do not survive their first year, while the average lifespan of terrorist organizations is around 8–9 years. Large groups tend to have a longer lifespan than smaller ones, especially if they form alliances. The chapter also looks into factors motivating groups to continue with violent attacks. Such factors include specific state and group characteristics and intergroup relations. It examines the instrumental model and the organizational model and looks into the rationality behind terrorist decision-making.
