When do women leave physics? Short answer: between high school and college. Afterwards, women and men perform approximately as you would expect at getting into grad school and getting jobs, given the dearth of women with bachelor’s degrees.
That’s the conclusion of this American Institute of Physics study (pdf), as reported in the New York Times. At the high school level, almost half of physics students are female (46% in 2003). But then less than a quarter of students who earn bachelor’s degrees are women. After that, women seem to advance at the same rate as men; the “pipeline” doesn’t seem to be all that leaky, except for the one huge geyser during undergraduate years. Which means that, among other things, it’s really hard to place the blame on something inherent in women’s brains, unless that something chooses to manifest itself only in college. (Meanwhile, college is the easiest place for systematic biases to be important, since that’s when students are choosing what fields to concentrate in.)
So, the news is mixed. There is good news in that the numbers continue to improve, and there’s every reason to believe we will eventually reach essentially fifty-fifty numbers of men and women in the field. According to the study, the percentage of Ph.D’s in physics that are awarded to women has gone from about 5% to over 15% in the last twenty-five years. Still a long way to go, but getting there. Also good news is that there doesn’t seem to be much discrimination at the highest levels of the academic food chain. (There certainly are fairly obvious individual examples of discrimination, but fortunately they don’t seem to be having a large impact overall.)
The bad news is that there is still a systematic bias turning women away from physics during the college years, and that we really do have a long way to go. While it’s true that things are likely to continue to improve, it’s not because the natural tendency of things is to automatically get better, but because people keep fighting for them to do so.
Oh yes, it’s also bad news for those rigorous scholars who propose that the leading causes of women’s underrepresentation are that they don’t want to work as hard, and that they lack the necessary intrinsic aptitude. Because studies like this show that those ideas are, how should we put it, inconsistent with the data. And therefore, by ordinary scientific standards, wrong. But don’t let that stop you from suggesting hypotheses!