Testing for the Effects of Concealed Weapons Laws: Specification Errors and Robustness

Abstract

In 1997, Lott and Mustard published an important paper which found that right-to-carry concealed weapons laws reduce violent crime. Although Lott and Mustard appear to do all possible variations of the analysis, a closer reading reveals that the study might suffer from several possibly important errors. I re-estimate the model and check for incorrect functional form, omitted variables, and possible second order bias in the t-ratios. Lott and Mustard's basic conclusions are generally robust with respect to these potential econometric problems. Overall, right-to-carry concealed weapons laws tend to reduce violent crime. The effect on property crime is more uncertain. I find evidence that these laws also reduce burglary.