Self-defense Regulations and Crime

Abstract

This paper uncovers the mechanism behind the relaxation of self-defense regulations with an empirical analysis followed by a game theoretical model. We obtained empirical evidence from examining the Stand Your Ground (SYG) law and subsequent changes in rates of planned and unplanned murder. We found that the SYG law increased planned murder rate by 7.6%, while it increased unplanned murder rate by 10.4%, on average across specification. Inspired by the differences, we built a game theory model based on Becker [1968] to explain the mechanisms. Faced with an increased likelihood of self-defense from the victim, some offenders of planned murder would be deterred, but others would prepare more thoroughly. Since offenders are often more experienced than victims in carrying out criminal activities, their improved preparations are likely to increase their success rate. On the contrary, offenders who act on-the-spot are less likely to improve their efforts more than the victims. In this case, if offenders are aggravated by victims’ defense, a more minor offense is likely to turn into murder. To decrease the success rate of planned murder, community-based approaches might be helpful (Makarios and Pratt [2012]). However, to prevent conversions of other kinds of crimes to unplanned murder, policy makers might want to reconsider the law.