Last updated: Thursday - May 29, 2008
Casey Cobb of the University of Connecticut pointed out similarities in the arguments of Fertilizers, Pills & Magnetic Strips (FPMS) and those in Steven D. Levitt and Stephen J. Dubner's Freakonomics: A Rogue Economist Explores the Hidden Side of Everything (2005, NY: William Morrow). Specifically, Levitt and Dubner's attempt to account for fluctuating crime rates as a long-term result of demographic changes is similar to my arguments about how changing U.S. demographics affect education and other institutions. Levitt and Dubner point out that in the years following the Roe v. Wade decision (January 1973), the number of abortions in the U.S. rose from three-quarter million to more than one-and-a-half million in 1980. By the early 1980s, one abortion was being performed for every 2.25 live births. Look at this another way: nearly a third of all pregnancies were terminated by abortion in the early 1980s. And that segment of society that was obtaining abortions shifted significantly as a result of legalization. Formerly, abortions were an expensive option chosen by the wealthy and upper-middle classes. After Roe v Wade, they became more affordable, didn't involve travel expenses, and were more available to young and poor women. The "hidden side" of the legalization of abortion (to which the authors refer in their subtitle) is that 15 to 20 years after Roe the U.S. crime rate show a remarkable decline. Levitt and Dubner attribute this decline to the decline in the population share of young, crime prone males. Their analyses rose above post hoc ergo propter hoc reasoning by means of a fine grained analysis of the data. States that had legalized abortion shortly before Roe was upheld by the Supreme Court showed an earlier decline in violent crime 15 to 20 years later than states that legalized it after Roe. Moreover, states with higher abortion rates showed greater decreases in crime two decades later.

In the early 1990s before the big crime decline became apparent, politicians and a host of experts had predicted that violent crime was on an upward spiral that would soon engulf the entire nation. President Clinton opined, "We know we've got about six years to turn this juvenile crime thing around or our country is going to be living in chaos." (Levitt & Dubner, p. 4) To everyone's amazement, crime statistics moved in exactly the opposite direction, dropping precipitously in the mid to late 1990s. By 2000, the U.S. murder rate was lower than at any time since 1965.

What is significant here is that various political and ideological interests claimed responsibility for the decline. Gun control laws were the cause, some maintained. Others credited the booming economy of the 1990s; still others claimed victory for innovative policing approaches. But more likely, a demographic shift originating in Roe v Wade was depleting the U.S. population of its most violent crime prone citizens.

How might all of this relate to Fertilizers, Pills & Magnetic Strips? In a couple of ways, perhaps. One angle not examined in FPMS is that long-term trends in achievement data should be looked at again in terms of the same demographic shifts that Levitt and Dubner have explored.

But a second sense in which Freakonomics is relevant to Fertilizers, Pills & Magnetic Strips is that the former has shown how readily partisans will pounce on data that appear to be favorable to their causes when in fact those data do nothing but reflect quite unrelated demographic shifts. How many phenomena (widening or narrowing achievement gaps; falling or rising drop-out rates; waxing and waning NAEP scores) are merely reflections of who is having more babies and who is having fewer?


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