More than one-third of physics departments in the United States lack a single female faculty member. That figure has been cited by some as evidence of discrimination. With women making up just 13 percent of the faculty members (assistant through full professors) in physics, could there be another explanation?
A new report  from the American Institute of Physics -- based on simulation analysis -- concludes that the large number of departments without a single woman is to be expected and is not the result of discrimination. Some experts on women and science, however, disagree.
The institute's report says that there are two factors that explain the distribution of women among departments: the size of departments and the total number of female faculty members available. There are many departments with only two or three physics faculty members, the report notes. So "it is unlikely that these departments will have a woman among the faculty because the overall representation of women among all physics faculty members is low," the report adds.
The report divides physics departments into two main categories: institutions that grant only bachelor's degrees (which tend to be smaller) and institutions that grant doctoral degrees in physics (which tend to be larger).
Physics Departments, Faculty Size and Gender
|Highest physics degree awarded||Bachelor's||Ph.D.|
|Smallest department (# of faculty members)||1||3|
|Median size of department (# of faculty members)||4||22|
|Largest department (# of faculty members)||27||75|
|Women's representation on physics faculty||16%||11%|
|Departments that have no women||47%||8%|
|Departments that have no men||1%||0%|
|Number of departments||503||192|
The institute ran simulations to show how the number of women would result in certain departments having women, and certain ones not having any. As an illustration, the first (hypothetical) simulation involved a pool of 1,000 faculty members -- half men and half women -- divided into 500 departments. About half of them would end up either all-male or all-female.
The next simulations involved the actual numbers of female faculty members, when situated in departments roughly the size of bachelor's and Ph.D. departments of physics.
Random selection of the available women into the generally small-sized bachelor's departments would yield 49 percent of departments with same-sex faculties, the institute found, roughly the proportion that exists now. Random assignment of the women in Ph.D.-granting departments would be expected to leave 12 percent of those departments without any women (greater than the actual 8 percent).
The report concludes by saying that the "sex composition of a physics department is the result of a multitude of events, some recent and some that go back many years. Based on these simulation results, though, we should not accept the absence of women among professorial rank faculty in a single department to be prima facie evidence of a bias against women."
Further, the report warns that too much focus on ending all-male departments may have negative consequences. "We must also recognize that having at least one woman among the faculty in more departments results in an increased number of women who are the only woman in their department," the report says. "Given the current representation of women among all physics faculty, this isolation of women faculty members is the, perhaps unintended, tradeoff that occurs when women, representing a small proportion of all physics faculty members, are found in more departments than expected."
Janet Bandows Koster, executive director and CEO of the Association for Women in Science, said via e-mail that the report "a disappointment."
She urged physicists to study the concept of "implicit bias," which she said might have something to do with the pool of women in the discipline. "We know that most people are reluctant to accept that they are biased, and scientists in particular pride themselves on their impartiality. Yet scientists are humans raised in societies, and thus are subject to collective messages that suggest men are suited to science because they are independent and analytical whereas women are better suited to care-giving and cooperative enterprises."
It's too easy, she said, to focus only on the relatively small number of women in the field. "Inferring there is no hiring bias because the 'n' is so small for female faculty is essentially like granting a papal indulgence to physics departments across the country," she said.