If I might add on to that, I believe the researcher to whom you're referring is referred to in the Doob and Webster article that is cited in our materials.
Doob and Webster spent about three pages explaining why Levitt's conclusions are inaccurate and misleading. Doob and Webster claim that he also ignores a large body of the evidence.
I'm quoting from the article:
Levitt's review focuses largely on only two studies--both his own (Kessler and Levitt 1999 and Levitt 1998)--as evidence “for a deterrent effect of increases in expected punishment”. (2002, p.445). In addition, two other studies are cited in which offenders were interviewed. However, this latter research relates more to individual deterrence than to general deterrence.
He goes on to say that Levitt is remarkably selective in the literature that he cites and then how, for the sake of completeness, he needs to elaborate on the evidence that Levitt has cited.
So I would draw the committee's attention to this article and to the analysis presented by Professor Doob.