Do Concealed Gun Permits Deter Crime? New Results from a Dynamic Model

Marjorie McElroy, Duke University
Peichun Wang, University of Pennsylvania

Setting off a fifteen-year controversy, Lott and Mustard [1997] famously argued that state shall issue laws (SILs) providing for the liberal issue of concealed gun permits reduce violent crime by deterring violent criminals. In this controversy the weapon of choice has been differences-in-differences estimates. We present and estimate a more general cohort panel data model (CPDM) of changes in the crime rate that accounts for forward-looking behaviors of potential and already dedicated violent criminals. Treating violent crime as a career, the model decomposes the effects of SILs into a direct effect on entry decisions, a surprise effect on exit decisions, and a selection effect on those who entered violent crime under the aegis SILs. Applying generalized least squares with autocorrelated errors to state-panel data on changes in the violent crime rate, our preliminary results provide only hints of support for the deterrence hypotheses.