Re: John Lott
"John Lott's Unethical Conduct
Posted on: February 1, 2009 11:47 PM, by Tim Lambert
John Lott is embroiled in several controversial affairs:
* he almost certainly fabricated a mysterious survey and certainly behaved unethically in making claims for which he had no supporting data
* he presented results purporting to show that "more guns" led to "less crime" when those results were the product of coding errors
* he pretended to be a woman called "Mary Rosh" on the internet in order to praise his own research and accuse his critics of fraud.
* he probably was the person who anonymously accused Steve Levitt of being "rabidly antigun"
The Mysterious Survey
John Lott has claimed that he conducted a survey over three months in 1997 that found that in 98% of defensive gun uses the defender merely has to brandish the gun to break off an attack. It is almost certain that he never did a survey because:
* nine published surveys give numbers ranging from 21% to 67% as to how often defenders shoot, far more than the 2% Lott claims
* Lott claims that his survey found defenders firing in 2 out of 28 cases, which is 7%, not 2%. Nor is it possible that the weighting scheme Lott now claims to have used turned 7% into 2%.
* no evidence that Lott ever conducted such a survey can be found
* Lott has repeatedly changed his story about the source of the 98% figure, variously attributing it to "national surveys" and some particular polls, only publishing the story about the survey in 2000.
* Lott made the 98% claim on Feb 6, 1997, well before his survey was completed.
* Lott changed his story about the survey.
* Despite extensive coverage on the net, in many papers such as the New York Times, the Chicago Tribune and the Washington Post, an ad in the alumni magazine and in the best-selling book Freakonomics, none of the eight students Lott claims conducted the survey have been heard from.
* Lott claims to have "replicated" his survey with a new one that gives 95% brandishing, when in fact the new survey found only seven gun users (one of whom fired), far too small a sample to yield a meaningful brandishing number. (And if you correct his arithmetic you get 91% anyway.)
* Lott was caught lying when he claimed "I have not participated in the firearms discussion group nor in the apparent online newsgroup discussions".
Best writing by bloggers on this is by Marie Gryphon, Kieran Healy and Mark Kleiman. Best articles by journalists are those by Tim Noah and Michelle Malkin. An annotated copy of Lott's response to Malkin is here. More details about the problems with Lott's claims are here. Also recommended are Otis Dudley Duncan's comments on scientific ethics and on Lott and surveys.
All of my posts on the mysterious survey.
Coding errors in More Guns, Less Crime data
In 1998, John Lott published a book entitled More Guns, Less Crime. In that book he presented statistical evidence that concealed-carry laws were associated with lower crime rates. My critique of his book is here.
In 2002, Ian Ayres and John Donohue analysed a more extensive data set and found that, if anything, concealed carry laws lead to more crime. Lott responded with a new analysis that he claimed confirmed the "more guns, less crime" hypothesis. Ayres and Donohue's response (April 2003) was devastating—Lott's data contained numerous coding errors that, when corrected, eliminated the results and, this was the second time these sort of errors had been found in Lott's data
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