Did Stand Your Ground Increase Florida Homicides?

Harvard's Anton Strezhnev has a fascinating post on the topic. Two previous studies have found that Stand Your Ground increases homicide, and, using an interesting method, Strezhnev finds that firearm homicides increased in Florida after the law passed. Strezhnev created a trendline for a "synthetic Florida" -- basically, what happened to Florida's demographics in other states -- and compared it with what happened in Florida itself:

There's a word of caution here, though: Basically, what this means is that homicides in Florida spiked in 2006 and fell only slowly thereafter, for reasons that were not present in other parts of the country. The question is whether it was Stand Your Ground that caused this, or rather some other Florida-specific factor(s).

After Stand Your Ground, justifiable homicides in Florida rose from about 12 per year to about 36. Meanwhile, murders rose by about 200. As Strezhnev says, it's possible that Stand Your Ground caused homicides that were not later ruled justifiable -- the law might have convinced people there was a chance that they'd get away with killings that they in fact did not. (An important unknown here: How many Florida murderers even knew about Stand Your Ground?)

But at the very least, this is a very big effect to attribute to a law that actually applied to only about 25 additional cases per year. It's also a bigger effect than the one found in either of the other studies he cites: This study says that about 30 additional killings occur each month in 18 states with Stand Your Ground laws combined (about 20 per year per state, though obviously population size matters); this study reports an 8 percent increase, which is less than half of the increase Florida saw in murder. And as this McClatchy story notes, the trends identified in the studies don't seem to appear in many states with Stand Your Ground.

This is a fairly young topic of study, and the recent attention it has received should spur an outpouring of research. It will be interesting to see how all of this pans out.

Robert VerBruggen is editor of RealClearPolicy. Twitter: @RAVerBruggen