Department of awful statistics

By Megan McArdle

I saw this on Feministing and thought: huh?

A new study by the Guttmacher Institute and the World Health Organization shows that abortion rates are similar in different countries whether the procedure is legal or not. Shocking, I know. Of course, what wasn't similar was the risk to women's health.

The study indicated that about 20 million abortions that would be considered unsafe are performed each year and that 67,000 women die as a result of complications from those abortions, most in countries where abortion is illegal.


Moral of the story? Safe, legal abortion is the best bet. Always.



This is a common meme among feminists; indeed, I myself was, in the long fled days of my youth, guilty of propagating it. I'm not quite sure why I thought that abortion was a magical exception to the rule that when you make something much harder and more costly to do, fewer people do it. In fact, the source for this oft-repeated claim turned out, when last I examined to to be fairly awful. This new claim comes with a better pedigree, but not, alas, noticeably better evidence. Here's what the New York Times has to say:

A comprehensive global study of abortion has concluded that abortion rates are similar in countries where it is legal and those where it is not, suggesting that outlawing the procedure does little to deter women seeking it.

Moreover, the researchers found that abortion was safe in countries where it was legal, but dangerous in countries where it was outlawed and performed clandestinely. Globally, abortion accounts for 13 percent of women’s deaths during pregnancy and childbirth, and there are 31 abortions for every 100 live births, the study said.

The results of the study, a collaboration between scientists from the World Health Organization in Geneva and the Guttmacher Institute in New York, a reproductive rights group, are being published Friday in the journal Lancet.

“We now have a global picture of induced abortion in the world, covering both countries where it is legal and countries where laws are very restrictive,” Dr. Paul Van Look, director of the W.H.O. Department of Reproductive Health and Research, said in a telephone interview. “What we see is that the law does not influence a woman’s decision to have an abortion. If there’s an unplanned pregnancy, it does not matter if the law is restrictive or liberal.”



I can't see the Lancet study, which is gated. But the summary does not back up this claim. The study says that abortions are generally high in the developing world, where it is usually illegal, and low in the developed world, where it is usually legal. It also tells you that abortion is relatively unsafe in the developing world.

But it seems mad to extrapolate this to a blanket statement such as "Law does not influence a woman's decision to have an abortion." For one thing, we know of cases where the law absolutely and indisputably did exert such an influence, such as Communist Romania, where abortion bans caused the birth rate to soar. For another, societies where abortion is illegal are probably different from societies where abortion is legal in other ways, such as attitudes towards birth control. Also, enforcement of laws varies even when the laws don't (abortion was technically illegal in Germany for most of the post-war period). And finally, since the variation is almost entirely among developed countries where access to birth control may be spotty for economic, political or social reasons, this would not necessarily tell us much about developed nations. As I understand it, most abortions in America are obtained by women who have had more than one abortion, which seems to indicate that for at least some segment of the population abortion is a substitute for birth control, rather than birth.

Similarly, saying that "making abortion illegal doesn't reduce its incidence, but only makes it more dangerous" is nonsense on stilts when the comparison is largely between developed countries with legal abortion, and developing countries with illegal abortion. Having an abortion in Burundi would be more dangerous than having one in America even if their government legalized the procedure, made it free, and awarded a medal and a complimentary fruit basket to every woman who had one. I am pretty sure that abortion, like almost every other activity, gets more dangerous when it is legally prohibited. But from what I can make out, this study doesn't do a good job of demonstrating that truism.

Cross-country comparisons--what statisticians call latitudinal studies--are fraught with difficulty because of all the differences in law, enforcement, data collection, social norms, political culture, health care systems, and so forth. That's why it's important to also look at longitudinal studies--studies that examine the same place over time. And all the reputable studies I'm aware of, which to be sure are not an exhaustive list, show pretty much the expected result: if you legalize abortion, you get more of it.

In America, especially, the evidence that legalizing abortion resulted in more abortions seems pretty rock solid. Steve Levitt wrote about this in Freakonomics, and I blogged an excerpt some time ago:

In the first year after Roe v. Wade, some 750,000 women had abortions in the United States (representing one abortion for every four live births). By 1980, the number of abortions had reached 1.6 million (one for every 2.25 live births), where it levelled off. . .

To be sure, the legalization of abortion in America had myriad consequences. Infanticide fell dramatically. So did shotgun marriages, as well as the number of babies put up for adoption (which has led to the boom in adoptions of foreign babies). Conceptions rose by nearly 30 percent, but births actually fell by 6 percent, indicating that many women were using abortion as a method of birth control, a crude and drastic sort of insurance policy.



I'm still in favor of legalizing it, of course, for moral and practical reasons that I've gone into elsewhere. But the case for legal abortion stands on its own. It doesn't need nonsense statistics to back it up.

This article available online at:

http://www.theatlantic.com/business/archive/2007/10/department-of-awful-statistics/2113/