Does the Right to Carry Concealed Handguns Deter Countable Crimes? Only a Count Analysis Can Say

An analysis of the effects of right-to-carry laws on crime requires particular distributional and structural considerations. First, due to the count nature of crime data and the low number of expected instances per observation in the most appropriate data, last-squares methods yield unreliable estimates. Second, use of a single dummy as a measure of the nationwide effect of right-to-carry laws is likely to introduce geographical and intertemporal aggregation biases into the analysis. In this paper we use a generalized Poisson process to examine the geographical and dynamic effects of right-to-carry laws on reported homicides, rapes, and robberies. We find that the effects of such laws vary across crime categories, U.S. states, and time, and that such laws appear to have statistically significant deterrent effects on the numbers of reported murders, rapes, and robberies