By Panu Poutvaara, Mikael Priks

This paper isolates the causal effect policing has on group violence. The problem of reverse causality from violence to policing is addressed us-ing a change in the allocation of the Stockholm Supporter Police following the 9/11 terrorist attack in September 2001 and the Tsunami Catastrophe in December 2005. We analyze unique data on supporter violence in Swe-den before, under, and after the period supporter police was reallocated to anti-terrorist activities and to Tsunami-related activities.

Munich:ifo Institute for Economic Research, 2006, 21p.