Lott has a new posting where he has some more about the important matter of the coding errors in his data. Sandwiched between some more complaints about unfair the Stanford Law Review has been and some imaginary errors in Ayres and Donohue, we have:
Of course, this is nothing new with their misleading attacks on David Mustard, where minor coding errors did not change what he had written. (Instead of letting David correct a small mistake which did not fundamentally change the results, David was forced to cut out what would have been a damaging evidence against Donohue. If correcting these minor points had changed the results in a way favorable to Donohue, why wouldn't they let David publish the figure that he wanted to publish?)
Furthermore, extending the data through 1998 produces results consistent with the basic Lott-Mustard conclusions. Figure 2 depicts the coefficient estimates from state-level regressions of the years before and after the Right-to-Carry laws go into effect for the four violent crimes. ... The passage of the law is associated with sharp decreases in murder, rape and robbery. Murder and robbery rates are higher in Shall-Issue states prior to the passage of the law and fall immediately after the law goes into effect. As in Figure 1, these drops are much larger than would be warranted by a reversion to the mean explanation because the post-law rates are substantially lower than the pre-law rates. Rape shows a slightly different pattern. Right-to-Carry states have similar rape rates as other states in the years prior to the law. However, these states experience sharp drops in rape rates after the law is implemented. Aggravated assault rates in counties that pass Shall-Issue laws are higher both before and after the law goes into effect, with little change before and after the law.
Now, Figure 1 uses one less year of data and groups years into pairs, but basically it should look similar to Figure 2. However, because of Lott's coding errors it looks dramatically different. How on earth can Lott call this "a small mistake which did not fundamentally change the results".
Lott refers to "minor coding errors did not change what he had written", but Mustard wrote
The passage of the law is associated with sharp decreases in murder, rape and robbery.
That describes figure 2 (the one affected by the coding errors) but not figure 1, which doesn't have any big decreases till eight years after the law (and even that decrease was because the set of states with eight years of post-law data was smaller than the set of states with six years of such data).
And can anyone discern what, in that deleted text, was the "damaging evidence against Donohue" that Lott claimed was cut. Anyone?
In summary, Lott's claim that his coding errors in his NAS panel analysis were "minor" or "small" and do not "fundamentally change the results" is completely false.