Empirical evidence reveals that unemployment tends to increase property crime but that it has no effect on violent crime. To explain these facts, we examine a model of criminal gangs and suggest that there is a substitution effect between property crime and violent crime at work. In the model,...

Democratic societies are challenged by various violent and organized groups, be they terrorists, gangs or organized hooligans. In exchange for offering an identity, leaders in such groups typically require members to be violent. We introduce a simple model to capture these stylized facts, and...

This paper isolates the causal effect of policing on group violence, using unique panel data on self-reported crime by soccer and ice hockey hooligans. The problem of reverse causality from violence to policing is solved by two drastic reallocations of the Stockholm Supporter Police unit to...