Kirsten Powers of Fox News took to The Daily Beast to make the bizarre case that birth control doesn't prevent abortions. In an attempt to show that abortion rates had remained suspiciously constant over the past decade, she accidentally compared the same 10-year-old study to itself. "I am deeply sorry for the error, which invalidates my piece," Powers later admitted in an author's note.
Anti-contraception cranks often cite research on populations to show that rates of contraception and abortion can rise in tandem. Then they use those studies to argue that birth control doesn't generally prevent abortions. But without a control group, you never know whether the abortion rate would have been even higher without birth control.
An estimated 85 percent of couples who are having regular intercourse without birth control will get pregnant within a year. Whereas, the typical use failure rate for birth control pills is 3 percent and the perfect use failure rate is .1 percent. The efficacy rates of major birth control methods have been rigorously tested, so we can make causal claims about how many unplanned pregnancies a particular method prevents, relative to unprotected sex.
About half of all unplanned pregnancies end in abortion in the U.S., no matter how many hurdles the anti-choicers put between women and the constitutional rights.
If you take 100 healthy couples who are having sex, but who aren't planning to get pregnant, and let them go at it for a year without birth control, you can expect about 85 pregnancies, and 42 abortions. If those same couples were using the Pill in the basically conscientious but slightly imperfect way that most people do, you'd expect about 3 unplanned pregnancies and 1.5 abortions. 42 is greater than 1.5. QED.
Obviously, birth control doesn't work if you don't use it, and the further you deviate from perfect use, the less reliable it is. Powers cites a study of women getting abortions as evidence that access to birth control doesn't decrease the abortion rate. Only 12 percent of women who weren't using birth control when they got pregnant cited lack of access as a reason why not. Powers claimed that not a single woman cited lack of access, but she got that wrong and The Daily Beast still hasn't fixed her mistake, despite my request for a correction. That relatively low percentage suggests that organizations like Planned Parenthood are doing a good job providing birth control to those who want it, regardless of their ability to pay.
As Amanda Marcotte points out at RH Reality Check, self-reports of reasons for not using birth control may not tell the whole story. There are all kinds of systemic barriers and hassles that discourage contraceptive use, or push typical use further from perfect use, and thereby increase the unintended pregnancy rate -- but which the average person probably wouldn't describe as an absolute lack of access. Having legal access to something in principle is not the same as having ready access to it at an affordable price.
There's an even deeper logical flaw in Powers' analysis, however. If you only look at women who are getting abortions, you only see cases in which birth control didn't work or wasn't used. You will miss the millions of people who successfully use birth control and therefore never need abortions.
For someone who already admitted that her entire argument is invalid, Powers got awfully defensive on twitter when Marcotte pointed out even more flaws in her reasoning.