Freakonomics errata

Freakonomics is a book about the hidden economics that govern stuff all around us. The writing is a little slow (I think the decision to present almost all the results at the beginning of the book and *then* explain them was not very good – no suspense whatsoever) but it is a very interesting read anyway (those interested in this subject might check out Blink which I found more fun to read).

Anyway, in the book there is a chapter that unveils a hidden reason behind the fall in criminality in the 80s : the legalization of abortion. This is a very powerful argument against pro-lifers, and a testimony on how incredibly complex human interactions are. However, it appears the authors made errors in their computer code that could mean the results are meaningless ! The Horror ! In a nice example of how science corrects itself, Steven D. Levitt (the main author) explains the consequences of the error, which are fortunately less bad than expected.

(from Deltoid, where Tim Lambert exposes some more hypocrisy. Une fois n’est pas coutume, mais presque)

Update : Apparently, the issue is not so clear-cut.  Steve Sailer has a very long page that supposedly exposes flaws in Dr. Levitt’s work. Even if the page is kinda hard to read (that might just be my lack of experience in economics showing) and the nice figures lack actual references, it’s enough to cast doubt… I guess it’s a good idea to keep an eye on future posts by Dr Levitt that might hopefully clarify things.

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5 Responses to Freakonomics errata

  1. JLott says:

    Of course, this discussion is not very accurate.

    1) There of course 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. The Stanford Law Review article by Plassmann and Whitley added an additional four years to the 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 and Whitley because it was very large and they 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.

  2. vnoel says:

    And this is relevant because … ?

  3. Steve Sailer says:

    You might be interested in the new article on the “Freakonomics Fiasco” at The Economist:

    Oops-onomics
    http://www.economist.com/finance/displayStory.cfm?story_id=5246700
    Dec 1st 2005
    From The Economist print edition
    Did Steven Levitt, author of “Freakonomics?, get his most notorious paper wrong?

    Obviously, I’m prejudiced, but I think the best introduction to the whole controversy remains the 1999 debate between Dr. Levitt and myself in Slate.com:
    http://www.slate.com/id/33569/entry/33571/

    In light of this week’s revelations about the fatal errors in Levitt’s econometric black box analysis, my series of reality checks on his theory seems, well, vindicated.

  4. jlott says:

    Because of your third paragraph.

  5. Tim Lambert says:

    That’s the closest Lott has ever come to acknowledging the existence of my blog.

    John, maybe you could have posted your comment at my blog where it was relevant (even if grossly misleading)?

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