Tyler Cowen labels this paper by Shu Kahn the "politically incorrect paper of the month." It's about the promotion and tenure prospects of women and men working in the sciences. Given the label, I was expecting it to conclude that women didn't get promoted because "math is hard!" In fact, it says:

We evaluate whether gender differences in the likelihood of obtaining a tenure track job, promotion to tenure, and promotion to full professor explain these facts using the 1973-2001 Survey of Doctorate Recipients. We find that women are less likely to take tenure track positions in science, but the gender gap is entirely explained by fertility decisions. We find that in science overall, there is no gender difference in promotion to tenure or full professor after controlling for demographic, family, employer and productivity covariates and that in many cases, there is no gender difference in promotion to tenure or full professor even without controlling for covariates. However, family characteristics have different impacts on women's and men's promotion probabilities. Single women do better at each stage than single men, although this might be due to selection. Children make it less likely that women in science will advance up the academic job ladder beyond their early post-doctorate years, while both marriage and children increase men's likelihood of advancing.

I don't know whether that conclusion's right, but I certainly don't think it's especially politically incorrect. You say the gap is explained by "fertility decisions" I say it's explained by "structural sexism." Here, as in much of life, women and men are now allowed to compete on "equal" terms. The terms, however, were set up long ago -- by men -- before that was the case, operating under the implicit assumption that the competitors would be men who, if they had children, would have wives at home to take care of the children. So things work out nicely if you're a man, or if you're a single woman, but not so well if you're a woman who -- like most women -- has children at some point. You can't just pin this problem on science departments and university administrators, since obviously larger social forces are at work, but it's hardly fair. And university administration genuinely concerned with the situation could do things to mitigate the situation, though probably they couldn't solve it all on their own.

As an alternative, they could spin stories about how their daughter didn't want to play with trucks as a way of displacing concern away from this phenomenon. You know, whatever.

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