Researchers at Texas A&M University, for a study published in the Journal of Human Resources, concluded that homicides had increased by 8 percent in the more than 20 states that had passed "castle doctrine" laws, many of which include Stand Your Ground provisions. That equals 600 additional homicides every year in those states, they wrote.
At the same time, however, the researchers found no detectable decrease in burglary, robbery or aggravated assault.
"Collectively, these findings suggest that incentives do matter in
one important sense: lowering the threshold for the justified use of
lethal force results in more of it," the authors concluded in the
report. "On the other hand, there is also a limit to the power of
incentives, as criminals are apparently not deterred when victims are
empowered to use lethal force to protect themselves."
As the Texas A&M researchers noted in that 2013 study, their
findings aligned with those of a 2012 study published by Georgia State
University on Stand Your Ground laws.
The Georgia State researchers found that homicides in states with
those laws increased by 7.1 percent. In particular, they detected an
increase in homicides among white males, while the effect was mostly
negligible among white females and blacks.
"Whether or not these killings should be considered justified in this
case is beyond the purpose of this paper," they wrote. "However, it
cannot be argued that the SYG laws are saving the lives of innocent
people in this scenario as these individuals would not have been killed
in the first place."