In the posting where he finally admitted that he had made hundreds of coding errors, Lott insinuated that Ayres and Donohue had refused to release their data and that their results were not reproducible.
Unlike Ayres and Donohue, I have endeavored to make the data readily available in a timely manner and to explain how it was constructed.
...
Ayres has also declined my requests for his data in the past, and my attempt to reconstruct what data is publicly available did not produce the same results that he claimed to obtain (e.g., p. 257, fn. 28).
Actually the data for Ayres and Donohue's paper is available here, and has been available since before the paper was published.
Lott's second paragraph is also highly misleading. He is referring to Ayres and Levitt's data on Lojack sales. If you read the paper that the data was used in, it is quite clear that the the sales data was commercial and confidential and that Lojack did not want it released. I'm sure that Ayres and Levitt would have had to agree not to release the data to any third party before Lojack provided it to them. The fact that they kept their word to Lojack gets transmuted by Lott to evidence of malfeasance on their part. And Lott's claim that their results were not reproducible is ridiculous. Lott had absolutely no sales data for Lojack at all, so he made a pure guess as to what the sales where and found, surprise, surprise, that he got a different result to what Ayres and Levitt got using real data.
Several people have been misled by Lott on this issue, including Kevin P. in this Calpundit thread, Captain Holly in this thread at The Warren, and Tom Wright, who wrote:
They also refuse to supply their own data, when Lott freely offers his on the web for anyone to see, researcher, journalist or layperson.
Unfortunately, this is not the only time that Lott has made misleading claims about others not releasing their data. In More Guns, Less Crime, he claimed that Kellermann had not released the data for his case-control data on homicide, even though Kellermann had released the data. And even though Lott was shown how to get the data in 1998, he did not correct his false claim in the second edition of More Guns, Less Crime.