It has long been a standard claim of economics—iirc, Robert Lucas was the first to say it aloud, though it may have been Gary Becker*—that a man who marries his housekeeper lowers GDP.
Apparently, Dubner and Levitt have taken this claim—along with their Rick James title**—to heart. Echidne has the details. A short sample:
There is one labour market women have always dominated: prostitution. Its business model is built upon a simple premise. Since time immemorial and all over the world, men have wanted more sex than they could get for free. So what inevitably emerges is a supply of women who, for the right price, are willing to satisfy this demand. But what is the right price?…
It turns out that the typical street prostitute in Chicago works 13 hours a week, performing 10 sex acts during that period, and earns an hourly wage of approximately $27. So her weekly take-home pay is roughly $350. This includes an average of $20 that a prostitute steals from her customers and drugs accepted in lieu of cash.
If I didn’t know that Levitt has done some research on prostitution, I would think he left this section solely to Dubner. As it is, the skewed perspective (supply-side only) wouldn’t even pass muster in a basic neoclassical labor market model, and that the authors are trying to sell this as “economics” is, to extend a recent note from Brad DeLong that “Levitt and Dubner today appear to no longer be thinking like economists”, going to do Levitt much more harm than good.
Perhaps the difference between prostitutes and economists is that only the former have to worry about their reputation.
*Google indicates that the source is Pigou (1932). Does this explain the popularity of the Pigou Club?
**At this point, I’m betting they chose the title because of Abigail Breslin.