What's going on?

What happened to the women in Chemistry? Why didn't it happen to women in Physics or Math? With no evidence but anecdata, I'm not about to draw a solid conclusion, but I can think of several possibilities.

Physics and Math are notoriously low on women. Perhaps because of that there are more efforts to get more women in those fields, versus Chemistry, which is nearing an even male–female split and may not see the need for continued recruitment of women.4

Computer science, though lacking women, doesn't match that pattern. There I'd guess that the much higher frequency of postgraduate employment makes a difference. Most Comp. sci. PhDs got jobs, not postdocs, and I suspect that differences in networking could be at play. Comp. sci. PhDs are overwhelmingly male, so it seems logical that these men would mostly know other men, and when it comes to passing along job openings or making hires, they'd hire men. This might also explain some of the patterns in Engineering, too.

That still doesn't fully explain Chemistry, neither does it explain Ag & Nat. Res. or Bio. & Biomed., where the gender difference is smaller, but women are still looking for work with greater frequency. Is this just old-fashioned bias? Is there something else going on? If the NSF numbers are from any point in the year, maybe women graduate later in the year than men, so less time will have elapsed for them between receiving the PhD and being counted in the survey.

Of course, there are plenty of other possibilities. This is just one year's data, and perhaps this has been changing (dare I hope improving?) over time. Whatever the reasons, though, it has me a little worried that in so many fields women are looking for work at higher rates than men. What gives, guys?

Other questions

The other thing I'd love to know is how this breaks down by race & ethnicity (in addition to field and gender). A physicist friend of mine has been looking for faculty jobs, and she's commented a number of times on the utter whiteness (and maleness) of so many physics departments. I didn't see numbers detailing both gender and race, but I hope that non-white, non-male PhDs are finding work (postgrad study, employment, etc.) at better rates than white guys because there is a lot of ground to cover before we reach equality in representation. I think it's really important that the PhDs coming out of graduate school look like the students they teach and the public they encounter.5 We need diversity to become so common it is no longer remarkable and surprising, but rather expected as the norm.

If you'd like to see more, I put together charts of postgraduation status for all6 physical sciences, life sciences and engineering fields. You can also dig through the data yourself. The NSF site has Excel files for each table, and apparently an interactive version is coming in January. There's tons more to learn.

1: I should note that the comparisons I'm making count only the respondents who provided information on their postgraduation status. See note b in any of the following tables: 57, 59, 63.

2: Yeah, maybe not scientific, but the criteria for the eyeball test are simple: (1) are the data sets "large enough" and (2) do the values look different? It turns out that I gauge differences >5% as significantly different. It also turns out that it's a decent approximation: run the pairs through a two-sample z test, and you'll find that the pairs I'd peg as different reject the null hypothesis (i.e. % men seeking = % women seeking) with confidence intervals >95%.

If I've just butchered Statistics, please point me to a place where I can learn more. My background in stats is much weaker than I'd like.

3: When you have only 35 women, as in Aerospace, Aeronautical & Astronautical Engineering, it takes only two women to make a 5% difference in study/employment status.

4: Interestingly, male and female PhDs in Math seem to have made different choices. They have the same frequency of seeking work, but more men went on for postgrad study, whereas more women got jobs.

5: Right now, the are so few black women in Physics that someone keeps a list. It has 56 names as of 2007; that's fewer people than were in my Chemistry cohort at UM when I started. I am not sure if these 56 are just PhDs from US universities, but it's still an incredibly small number. For comparison, the 2012 NSF survey includes 391 women who earned PhDs in Physics and have a postgraduation status reported. Those 56 names are not one year, they go back to 1972.

I was pleased to learn that UM appears to be one of the more supportive universities in the list, having been the alma mater of Willie Hobbs Moore (first black woman to get a Physics PhD) and four other women since. Only MIT has more alumnae on the list.

6: Okay, technically not all of them. I left out the engineering fields with <200 women.