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 … violence increased dramatically during these periods. …

hooligans reap utility from violence and social identity and study the effects of different police strategies. We find that an … increase in discriminative policing, provided by intelligence units, for example, always reduces violence. Under the right … circumstances, it may also lead to larger supporter clubs and a significant drop in violence. Indiscriminate policing, such as the …