Withdrawal study: Ur doin' it wrong
The conventional wisdom is that withdrawal is to contraception what bulimia is to weight-loss. Both methods have a certain mechanical plausibility, but no responsible physician would recommend either one.
Sex educators tend to regard withdrawal less as a form of contraception and more as an excuse not to use birth control. A researcher from the Guttmacher Institute and her co-authors are urging sex educators to reconsider, leading off a recent paper in the journal Contraception with the following bold hypothesis: "[Withdrawal] might more aptly be referred to as a method that is almost as effective as the male condom." (.pdf)
In the large print, the paper says the typical use failure rate for withdrawal is 18%. That sounds pretty good juxtaposed with the 17% typical use failure they cite for condoms. A footnote adds some additional context: "Notably, the typical-use failure rate for withdrawal is more variable, ranging from 14%-24%, compared to a confidence interval of 15%-21% for condoms."
According to the Guttmacher Institute's website, withdrawal's perfect use and typical use failure rates are 4% and 17.4%, respectively. The typical use figure on the website comes from the same study that the authors of the Contraception paper cited. (To put these numbers in perspective, 85% of couples who don't use any contraception will get pregnant within a year.)
The authors have gotten a lot of play out of their claim that, when used perfectly, withdrawal has an estimated annual failure rate of 4%, compared to 2% for perfect condom use. Where did that impressive sounding 4% perfect use figure come from?
A footnote in Guttmacher's online table explains: "Most perfect-use rates have been clinically evaluated, but some are based on clinical expertise or “best guesses” (such as some forms of periodic abstinence, withdrawal and no method use)." So, that dramatic 4% number comes down to the best guess of someone at the Guttmacher Institute? If so, the authors should have made that clear in the journal article.
The authors define perfect use as the man pulling out before ejaculation every single time, a definition that risks begging the question. If you only count the couples where the man always manages to pull out in time, every single time for a year, withdrawal might look pretty good. The "oops factor" is, after all, the main reasons sex educators discourage the practice. If you're going to define perfect use as perfect execution, you also have to compare the percentage of people who try to use withdrawal and fail vs. those who manage to screw up other methods.
The authors also admit that withdrawal is basically scientifically untested as a form of contraception. What little research exists comes from interviews and surveys, often from small studies of very specific populations, like Asian Canadians seeking abortions and Turkish factory workers. There has apparently never been prospective clinical trial of withdrawal.
The paper ends with a recommendation that, "[h]ealth care providers and health educators should discuss withdrawal as a legitimate, if slightly less effective, contraceptive method in the same way they do condoms and diaphragms." That's a totally irresponsible conclusion based on their evidence.
It's one thing to say that withdrawal seems to be better than nothing, it's quite another to suggest the practice as a long-term birth control method on par with condoms.
Predictably, the ABC website is running an uncritical story about the study under the headline: "'Pulling Out' Method Gets New Respect: Study says withdrawal is "better than nothing. Women react with 'sheer disbelief.'" Oh, those silly women with their obsession with logic and evidence.