Do Immigrants Cause Crime?.

We examine the empirical relationship between immigration and crime across Italian provinces during the period 1990-2003. Drawing on police administrative records, we first document that the size of the immigrant population is positively correlated with the incidence of property crimes and with the overall crime rate. Then, we use instrumental variables based on immigration toward destination countries other than Italy to identify the causal impact of exogenous changes in Italy's immigrant population. According to these estimates, immigration increases only the incidence of robberies, while leaving unaff ected all other types of crime. Since robberies represent a very minor fraction of all criminal o ffenses, the eff ect on the overall crime rate is not signi cantly di fferent from zero.