1. deltoid
  2. Lott's data-mining

Lott's data-mining

By tlambert on May 15, 2003.

ArchPundit has a thoughtful analysis of the latest from Reynolds and Lott.

Shorter dsquared: If you use some data to construct a model, then to test it properly you need new data. Lott's approach is a little different. The model that was given greatest prominence in the original Lott and Mustard paper (the results of this model where given in the abstract and whenever Lott summarized his paper) showed that there was a 3.5% decline in the violent crime rate associated with the carry laws. In the second edition of More Guns, Less Crime Lott has a chapter where he gives the results he obtained by adding four more years of data. Except that he uses a different model. Nowhere does he present the results you get with the original model. Why not? A clue to the mystery appears in Ayres and Donohue's paper. Table 10 shows that with five extra years of data, Lott's original model indicates that the change in the violent crime rate associated with the carry laws was 0.0%.

Tags
More Guns Less Crime

More like this

Did Lott cook his "More guns, Less crime" data?
This is a long post, so I'll start with two summaries. One sentence summary: It looks as if Lott might have been caught cooking his "more guns, less crime" data. One paragraph summary: Ian Ayres and John Donohue wrote a paper that found that, if anything, concealed carry laws lead…
Reply to Verdon
Steve Verdon has responded to my critique of More Guns, Less Crime. Verdon starts by claiming that Lott's argument doesn't depend on their being more guns or less crime. He argues that you just need "more people carrying (concealed) existing guns legally" and that Lott found a…
Lott's reply to Mother Jones
Lott has posted some criticism of Chris Mooney's article. Let's see how many errors he has successfully identified: 1) Paraphrasing claim from the Chronicle of Higher Education stating that the "coding errors had not been reviewed by a third party." I was never asked by the…
Using Placebo Laws to Test "More Guns, Less Crime"
Helland and Tabarrok's paper 'Using Placebo Laws to Test "More Guns, Less Crime"' has been published in Advances in Economic Analysis & Policy. Their objective was to correct for serial correlations in the crime data. I explained earlier how, if crimes rates in adjacent…