[T]he empirical analysis presented here provides no support for the contention that gun control reduces crime rates. In none of the regressions for the 10 categories of crime rates in 1999 and the 10 for 2001 is the measure of gun control statistically significant. The article tests another hypothesis, namely, that lax gun control laws in neighboring states undermine the effectiveness of state gun laws. It finds no support for this hypothesis. The proxy for neighboring state gun control is never significant in any of the 20 regressions estimated.
By contrast, the article provides empirical support for the idea that high crime rates generate political support for the adoption on more stringent gun controls. Moreover, there is empirical evidence that the probability of adopting more gun regulations is positively related to the proportion of Democrats in the state legislature.
Note that the authors' work neither confirms nor denies Lott's controverted study about the effect of concealed carry laws.