In the spirit of Lewis Richardson’s original study of the statistics of deadly conflicts, we study the frequency and severity of terrorist attacks worldwide since 1968. We show that these events are uniformly characterized by the phenomenon of “scale invariance,†that is, the...

A growing number of datasets collect information reflecting the behavior and characteristics of contentious and violent organizations. Most of these datasets are not arranged so that they can be easily combined for analytical purposes. In particular, there is a lack of common identifiers for...