argument, but I confess that at first blush it strikes me as implausible. To me, Lott’s general argument is supported even though it is hard to assign its effect to a particular year. Estimating the effects of RTC laws by individual years reduces the number of observations and thus the likelihood of finding a statistically significant effect. It is possible that doing this is proper, but it strikes me that such an argument ought first to be tested in a peer-reviewed journal before it is used in this report as a sound strategy.
Even if the use of newer data calls into question the original Lott findings, a more reasonable conclusion is that Lott’s findings depend on crime rate trends. The committee correctly notes that between 1977 and 1992 crime rates were rising rapidly while between 1993 and 1997 they were declining. Lott’s original study was of the first time period. Suppose that his results are not as robust for the second period. The committee concludes that this shows that his model suffers from “specification errors” (page 141). Another and to me more plausible conclusion is that the effect of RTC laws on some crime rates is likely to be greater when those rates are rising than when they are falling. When crime rates are rising, public policy interventions (including deterrence, incapacitation, and RTC laws) are likely to make a difference because they create obstacles to the market and cultural forces that are driving crime rates up. But when crime rates are falling, such interventions may make less of a difference because they will be overwhelmed by market and cultural changes that make crime less attractive. This may or may not be a reasonable inference, but it is worthy of examination.
In sum, I find that the evidence presented by Lott and his supporters suggests that RTC laws do in fact help drive down the murder rate, though their effect on other crimes is ambiguous.