More Guns Less Crime?

For those who don't know the background to this, Lott and Mustard published "Crime, Deterrence, and Right-to-Carry Concealed Handguns" in the Journal of Legal Studies in 1997. It spawned a bunch of papers (the original JLS has 165 cites according to google scholar).

Ayres and Donohue published a 2003 Stanford Law Review piece (disclosure: law review articles are not peer reviewed which doesn't help their case) that finds if you extend the original Lott and Mustard time series a few years, the "right-to-carry concealed handguns" laws no longer have an effect on crime. That is, they claim the original findings were an artifact of the number of years they used in their data.

Now I see that Marvel and Moody have a comment in the September issue of the Econ Journal Watch called The Debate on Shall-Issue Laws that do the same thing as the 2003 Stanford Law Review piece - they extend the data even more years, and the results return. Ayres and Donohue are invited to respond and will in the next issue (2009) of the journal.

Very interesting turn of events. I'm printing it out now. If their results hold up, then it seems like may be back to that same place of not really knowing the answer to the question. Typical of economics.