The Akin controversy has brought a lot of ugliness to light. I’ll push aside the broader political issues, which I’ve discussed on the other blog. Instead, I want to focus on a particular piece of nonsense from one of the more influential pro-Life figures, who has tried to argue that rape pregnancies are very rare.

You would think this would be straight forward. You could, for example, find rape victims and ask them if they got pregnant. And indeed, a study estimated that about 5% of rapes end in pregnancy and 32,000 fetuses are conceived in rape every year. You could also ask women getting abortions if they were raped. And indeed, Guttmacher did this and produced a lower estimate of about 10,000 or so. There is no real incentive, at this point, for women to lie about how they got pregnant. Or there are just as many reasons for them lie either way since many women are tragically ashamed of having been raped. But there is no a priori reason to suspect that either number is greatly inflated.

(The Guttmacher number seems a little better since the numbers in the former study would indicate about 640,000 rapes a year or three times what the FBI and NCVS conclude, even including the under-reporting factor. The difference is likely that Guttmacher is recent and Holmes was published in 1996, shortly after crime rates peaked. Rape rates have plunged in the last 16 years and are down about 85% over the last 30.)

But plain facts aren’t enough for some people, so John Wilke, “M. D.” has come up with a bizarre rape equivalent of the Drake equation to try to figure out how many rape babies are conceived every year and come up with a vanishingly small number.

It’s fairly easy to tear apart.

Continue reading Mathematical Malpractice Watch: Rape Statistics →