FLAWED GUN POLICY RESEARCH COULD ENDANGER PUBLIC SAFETY

A highly publicized recent study by Lott and Mustard concludes that la ws easing restrictions on licenses for carrying concealed firearms in public substantially reduce violent crime. Several serious flaws in th e study render the authors' conclusions insupportable. These flaws inc lude misclassification of gun-carrying laws, endogeneity of predictor variables, omission of confounding variables, and failure to control f or the cyclical nature of crime trends. Most of these problems should bias results toward overestimating the crime-reducing effects of laws making it easier to carry concealed firearms in public. Lott and Musta rd's statistical models produce findings inconsistent with criminologi cal theories and well-established facts about crime, and subsequent re analysis of their data challenges their conclusions. Public health pro fessionals should understand the methodological issues raised in this commentary, particularly when flawed research could influence the intr oduction of policies with potentially deleterious consequences.