In Lott’s latest entry he has given up trying to support his claim that
“the sensible girl ran for where the family guns were stored. But they were locked up tight.”
and responded to this post, where I pointed out that Cummings et al clearly stated that they controlled for national trends, but Lott none the less dismisses their results, claiming that they did not control for national trends. Lott now writes:
We had been unable to replicate their claimed results using fixed effects and the only way we could get something similar was without fixed effects. It really shouldn’t have been that difficult for us to confirm what they found since we were used their dates for the laws. Unfortunately, Cummings, Grossman, Rivara, and Koepsell were unwilling to give us their data when we asked for it. I asked for the data from Cummings and one other coauthor. Possibly we should have made a big deal of yet more academics who refused to share their data, but we decided that the more straightforward approach would be to simply say what we found. Alternatively, we could have simply stated that we were unable to confirm their results.
Yes, it would have been better to state something that was true instead of claiming that Cummings et al did not use fixed effects when they clearly stated that they did
Lott has knowingly misled the readers of his book. Someone who reads his book without carefully crosschecking it with Cummings et al is left with the impression that Lott’s work trumps Cummings because Cummings did not control for national trends. If Lott had instead made true statements about Cummings’ paper, readers would be aware that researchers using similar data and methodology had gotten different results and that the issue was in dispute.