We exploit exogenous variation in legal status following the January 2007 European Union enlargement to estimate its effect on immigrant crime. We difference out unobserved time-varying factors by (i) comparing recidivism rates of immigrants from the "new" and "candidate" member countries; and (ii) using arrest data on foreign detainees released upon a mass clemency that occurred in Italy in August 2006. The timing of the two events allows us to setup a difference-in-differences strategy. Legal status leads to a 50 percent reduction in recidivism, and explains one-half to two-thirds of the observed differences in crime rates between legal and illegal immigrants.
Mastrobuoni, G. and Pinotti, P., 2015. Legal status and the criminal activity of immigrants. American Economic Journal: Applied Economics, 7(2), pp.175-206.