Copying is the sincerest form of flattery?

From Friday's Wall Street Journal, an article by Mike Cox on the DC gun ban notes that:

Crime rose significantly after the gun ban went into effect. In the five years before the 1976 ban, the murder rate fell to 27 from 37 per 100,000. In the five years after it went into effect, the murder rate rose to 35. In fact, while murder rates have varied over time, during the 30 years since the ban, the murder rate has only once fallen below what it was in 1976.

From a piece that I wrote in 2004

Crime rose significantly after the gun ban went into effect. In the five years before Washington's ban in 1976, the murder rate fell from 37 to 27 per 100,000. In the five years after it went into effect, the murder rate rose back up to 35. . . . In fact, while murder rates have varied over time, during the almost 30 years since the ban, the murder rate has only once fallen below what it was in 1976.

This involves only three sentences that total 172 words in the piece, but it is still a little irritating. There were two changes in what I wrote: 1) because three years have gone by since I wrote the original piece the "almost 30 years" that I wrote was changed to "30 years" and 2) "fell from 37 to 27" was changed to "fell to 27 from 37." Otherwise it was identical. The first change is most troublesome because it indicates that Cox (or someone who wrote it for him) probably looked at what I wrote and the date on it in order to make the change.

This is getting to be a fairly common "crime" these days for example with Law Professor Ian Ayres being one of the more recent people caught:

“Several passages in Yale Law School professor Ian Ayres ... new book are unattributed verbatim reproductions or nearly identical paraphrases of passages from various newspaper and magazine articles published in the last twenty years, an investigation by the [Yale Daily] News has shown."

Yet, as some have noted in Ayres' case, "The problem with [Ayres'] explanation---whether used by Ayres or the others---is that it explains how a verbatim quotation can end up unattributed but is not so credible in explaining how an almost-verbatim paraphrase ends up unattributed. . . . But paraphrases in which the sentence structure is altered ever so slightly is much harder to explain as the result of inadvertence."

Incorrect claims about the data in More Guns, Less Crime

I have received an email comparing my work to that of Steve Levitt's regarding claimed coding errors in More Guns, Less Crime. Of course, this discussion is not very accurate.

1) There are no coding errors in the data used in “More Guns, Less Crime.” The book used crime data from 1977 to 1996, and as far as I know, no academics have claimed that there were any coding errors in that data. An interesting and useful Stanford Law Review article by Plassmann and Whitley added an additional four years to the data and the problem arose in this additional data. Overall, less than 200 cells out of 7.5 million cells were accidentally left blank. More important, the results that Plassmann and Whitley noted were the results which they thought were the correct ones were not affected at all by this minor change in the data.

2) I had put the data set on my website as a favor to Plassmann because it was very large and he did not have the ability to put it up for people to download. The data was corrected as soon as the missing cells were discovered and it was available for people to download. A note was added to the site to alert people to the correction. While I had helped them out on their paper, I let Plassmann and Whitley make their own statements about their results. My website reported the regressions in the same way that I had done them in all my previous estimates.

3) In statements here and here, I have discussed what was involved in Levitt's errors. The regressions where they left out the fixed effects were essentially the only ones that were at all useful in testing their hypothesis because they were the only ones that didn't require large degrees of aggregation to get to their "effective abortion rate" that were related to total murder rates in a state. The work that I did with Whitley directly related the age of the murder to the number of abortions when that murderer was born.

Thanks to Bob Thomas for his email.