More Sex is Safer Sex

Before there was “Freakonomics,” before there was “The Tipping Point” or “Blink,” Steven E. Landsburg wrote a regular column for Slate magazine called Everyday Economics. The column started in the summer of 1996 with an article headlined “More Sex Is Safer Sex,” in which Landsburg argued that H.I.V. would spread less quickly if relatively chaste people each took on a few more sexual partners. At a given bar on a given night, he wrote, these disease-free singles would then make the pool of sexually active adults safer. The article was based largely on an academic paper by another economist, Michael Kremer, theorizing that the spread of AIDS could be slowed in England if everybody with fewer than about 2.25 partners got around a bit more.
This research was one of the early examples of the economics profession’s imperialist movement. For the last decade or so, economists have been increasingly poking their fingers into other disciplines, including epidemiology, psychology, sociology, oenology and even football strategy. These economists usually justify their expansionism on two grounds: They say they’re better with numbers than most other researchers and have a richer understanding of how people respond to incentives.
Arrogant as this sounds, there is some truth to it. Besides, the public seems hungry for the kind of real-world social science economists are practicing. “Freakonomics,” by Steven Levitt and Stephen Dubner, has spent more than 100 weeks on the New York Times best-seller list, while Malcolm Gladwell, the author of “The Tipping Point” and “Blink,” has become perhaps the nation’s most popular nonfiction writer by artfully explaining the science behind everyday human interactions.