Revisiting John Donohue's cancelling of our gun debate last fall
2) Unfortunately, the second planned debate was also cancelled. The debate was rescheduled for April 13th this year, and I made sure to reconfirm it because of the previous cancelation. The student at Chicago who set up the debate said that even though he had confirmed the debate with me multiple times and even though we had taken a date that I was told that Donohue wanted, the claim is that the debate somehow hadn't been completely confirmed with Donohue. (You would think that if the previous cancelation was an accident, Donohue would have been careful to double check this time just in case there had been any possible misunderstandings, but no one is claiming that he checked anything.) Attempts were made to get Donohue's coauthor Steve Levitt to substitute for Donohue and debate either guns or abortion claims were unsuccessful. From an email that the organizer sent me after the second debate was cancelled: "You have been the most patient and flexible speaker I could imagine . . . ."
3) In conversations with Joe Cascio (the speaker coordinator for the UC Fed Soc Chapter), I had said several times if we were going to schedule a third try at a debate, we should do it on the abortion and crime claims, especially given the amount of attention that this poorly done empirical claim had gotten. Despite Donohue claiming that the debate would actually take place this time, he was unwilling to debate this hot topic. Steve Levitt was unable to debate (he was debating the topic but only with people who didn't seem to know much about the issue) and Dubner, Levitt's coauthor, was unwilling to debate the abortion claims. The University of Chicago Federalist Society was again willing to have me give another talk that wasn't in a debate format, but they insisted that I remove the statements regarding the canceled debates from my website. (They simply viewed my posts about the April 13th event being critical of the Federalist Society (I disagree), and the earlier post that they wanted removed because they didn't want to be involved in a debate about a debate.) I told them that I would correct anything that they told me was wrong, but I wasn't going to remove the postings. If people set up debates and back out at the last moment, they should be held accountable.
On the substance of Donohue's work on guns, I would direct people to this paper by Plassmann and Whitley. There are two straightforward points that they make. 1) That the graphs at the beginning of the Ayres and Donohue work are very misleading because they don't make it clear that the sample of states is changing. The crime rates clear fall for a decade and a half and the sudden increase isn't real for the remaining states. It just looks like an increase because the couple of rural states that remain did not experience the decline in murder rates that more urban states experienced after right-to-carry laws were passed. 2) The second claim has to do with them fitting an intercept and line to the data and then limiting their reported impact on crime to only five years. Often there is no problem with this, but as Plassmann and Whitley clearly show it doesn't fit in this case. The Ayres and Donohue approach implies that crime initially increase (despite the fact that the year by year data discussed in point (1) doesn't, and it is just an artifact of their estimates over predicting in the early years because they are fitting this straight line with an intercept shift to crime that is falling at an increasing rate. But to compound the problem, they only discuss what the estimates mean for the first five years. Even with this approach if they had picked the sixth year it would have reversed their claims.
I also think that it is pretty clear why they find it difficult to debate either guns or abortion. Steve Landsburg was very nice to suggest in April that Levitt and I have a discussion at Rochester this fall, but I haven't heard anything back. I immediately wrote back saying that I was interested. Landsburg wrote in April that:
I am posting this because of an email that I received asking questions about Donohue's cancelation last fall.