To try to explain the mechanism behind these patterns, the team borrowed a simple computer model from economics. The model treated all insurgencies like a marketplace--groups of people constantly deciding whether to act. Rather than coordinating, the groups simply watch the news. The size of the carnage reported at any given time determines the probability that a group of a given size will strike next. Like clockwork, the attacks over the course of the conflict--from the smallest to the most deadly--have the same distribution.
