A new NBER paper examines the effect of Stand Your Ground self-defense laws, which “eliminate the longstanding legal requirement that a person threatened outside of his or her own home retreat rather than use force.” Chandler B. McClellan and Erdal Tekin exploit cross-state variations in implementation dates to determine the effect of these laws on homicides. Their findings are grim:
Our results indicate that Stand Your Ground laws are associated with a significant increase in the number of homicides among whites, especially white males. According to our estimates, between 4.4 and 7.4 additional white males are killed each month as a result of these laws. We find no evidence to suggest that these laws increase homicides among blacks. Our results are robust to a number of specifications and unlikely to be driven entirely by the killings of assailants.
In the paper, the authors add that:
It is possible that some of the additional homicides associated with the SYG law may indeed be driven by the homicides of assailants. However, note that the net increase in homicides cannot be accounted by a one-to-one substitution between killings of assailants and killings of innocent individuals unless multiple assailants are killed in some instances (Cheng and Hoekstra, 2012). If at least some of the additional homicides are due to individuals resorting to the use of deadly force against each other in situations where the threat of death or serious bodily injury is not imminent to either party, this could indicate that these laws impose serious costs not only on criminals both also private citizens as well. It is also possible that potential intruders and attackers, who, in the absence of SYG laws, could have gotten away with their crimes without killing anyone, are now killed as a result of these laws.
Eighteen states have passed Stand Your Ground laws since 2005.