Assessing the Impact of Florida’s ‘Stand Your Ground’ Law on Homicide

• In Event: Gun Possession and Its Consequences

Abstract

Since 2005, a number of U.S. states have amended their self-defence laws, removing the “duty to retreat” principle. “Stand your ground” laws give individuals legal immunity for use of lethal force in situations in which they perceive threats. Critics are concerned that weakening the punitive consequences of using lethal force may serve to escalate aggressive and violent encounters. This study examines the impact of the first SYG law on homicide rates in Florida. An interrupted time series analysis was performed using state-level rates of homicide between 1999 and 2014. Seasonally adjusted segmented Poisson regression models were used to assess whether the onset of the SYG law was associated with a deviation from the underlying trend. We found an abrupt increase in monthly homicide rates of 24.7% associated with the onset of Florida’s SYG law (RR 1.25; 95% CI: 1.17–1.33, P=<0.001). The removal of a “duty to retreat” in Florida is associated with a substantial increase in the homicide rates. This suggests that the change in the law may have served to escalate the severity of harm incurred from violent altercations.

Authors

• David K. Humphreys, University of Oxford

• Antonio Gasparrini, London School of Hygiene and Tropical Medicine

• Douglas J. Wiebe, University of Pennsylvania