Tuesday, September 26, 2006

John Tierney, The Scientist of Sex Differences

The New York Times does have an interesting stable of conservative columnists. I've mentioned this before, but I still find it astonishing that the two best known wingnuts there, David Brooks and John Tierney, throw out so many column inches on the topic of women's rights. You might even think that this is some odd kind of affirmative action for male feminists. Except that neither Tierney nor Brooks ever writes in support of women. One day I'm going to do a retrospective of this phenomenon, with statistics and frequency distributions and other Truly Masculine Conclusions.

Today's Tierney topic is the Academy of Politically Correct Sciences. By this title Tierney refers to the new report from the National Academy of Sciences on women in sciences and engineering:

I've slogged through enough reports from the National Academy of Sciences to know they're often not shining examples of the scientific method. But — call me na├»ve — I never thought the academy was cynical enough to publish a political tract like "Beyond Bias and Barriers," the new report on discrimination against female scientists and engineers.

This is the kind of science you expect to find in The Onion: "Academy Forms Committee to Study Gender Discrimination, Bars Men from Participating." Actually, it did allow a total of one man, Robert Birgeneau of Berkeley, on the 18-member committee, but that was presumably because he was already on record agreeing with the report's pre-ordained conclusion: academia must stop favoring male scientists and engineers.

How this favoritism occurs is difficult to discern, particularly if you make it through all 291 pages. Donna Shalala, the Clinton administration veteran who led the committee, begins the report with a story of male chauvinists refusing to give tenure to a promising young scholar (herself) just because she was a woman, but that happened three decades ago. Buried deep in the report is a more recent datum: when a woman is up for tenure today in science or engineering, her odds of being approved are the same as a man's.

The report says that women are discouraged from going into science because of social pressure and "unintentional" and "unconscious" biases — which may well exist. But Shalala's committee is so determined to blame everything on discrimination that it dismisses other factors without giving them a fair hearing.

I bolded the bit which shows one of the few nice things Tierney has ever said about uppity women's arguments perhaps containing a grain or two of truth. Thank you, John!

The rest of the column is an argument that the mean feminists are ignoring SCIENCE. Tierney's concept of science needs to be in all capitals, because for him science is only that part of science which promotes the conclusions he already holds. All other conclusions from science are not SCIENCE but Political Correctness. For an example of what I mean, read this article on how SCIENCE is sometimes created.

Science tells us that there are more boys scoring really high on the mathematical part of the SAT. SCIENCE tells us that this means all men who hold high positions in science and mathematics had really high SAT math scores. Science may tell us (I'm not sure) that teenaged boys are interested in inorganic things and abstract thought and girls in communication and the sciences that deal with human beings. SCIENCE tells us that this makes adult men and women like that, too, for the rest of their lives. And although science doesn't tell us that girls are somehow biologically uninterested in engineering and science, well, a scientist does:

After decades of schools pushing girls into science and universities desperately looking for gender diversity on their faculties, it's insulting to pretend that most female students are too intimidated to know their best interests. As Science magazine reported in 2000, the social scientist Patti Hausman offered a simple explanation for why women don't go into engineering: they don't want to.

"Wherever you go, you will find females far less likely than males to see what is so fascinating about ohms, carburetors or quarks," Hausman said. "Reinventing the curriculum will not make me more interested in learning how my dishwasher works."

I have never had any interest in becoming an opera singer, and I have never met a single woman opera singer. This proves that women are not interested in opera singing as a career. Sigh.

Let's give Tierney's arguments closer scrutiny: First, I seriously doubt that a report of 291 pages contains no other evidence of discrimination than the Shalala statement at the beginning and the piece about the chances of actually being awarded tenure being identical for men and women in sciences and engineering. I really should read the report and if someone is willing to give me an extra twelve hours in a day I will.

In the meantime, I want to dissect Tierney's intention here: He wants to give the impression that discrimination existed a long time ago but that now things are fair and just. But note that thirty years is not a long time. For example, John Tierney had already been born then and had probably had his gender ideas fairly well fixed. And note the idea in the last quote, the one about "after decades of pushing girls into science and universities desperately looking for diversity". This is meant to make us think that enough is enough, nature has triumphed and we have done our utmost to make things easier for women than men. The problem, once again, is that thirty years is not a very long time. It's a blip in the history of what amounts to patriarchy, and the people in power today were almost all already alive thirty years ago. Commenters like Tierney argue that the experiment in feminism should be over. I argue that if Tierney had lived in the early nineteenth century he would have ranted and raved how biologically obvious it is that women can't attend college at all.

Then the argument that girls and boys may do equally well in mathematics but that this doesn't matter very much, because the scientists and engineers come from the extreme upper tail of the SAT distribution in mathematics, and that upper tail has a lot more boys than girls. In short, the group out of which scientists are drawn is predominantly male. A great argument, isn't it? At least if you assume that one test adequately measures all the characteristics that are necessary to make a scientist, if you assume that the test taken during teenage years measures ability forever more and if you assume that the questions are fair and gender-neutral.

Perhaps not:

This argument assumes two things:

1) A high measure of mathematical ability as measured by cognitive testing is required for technical disciplines like engineering, mathematics, computer science, and physical science college majors and careers. (I shall henceforth refer to these as EMS disciplines because that is the terminology used in the paper I want to talk about.) This is not to suggest that math itself is not involved; rather, I am just pointing out that this argument is predicated on the idea that A) the mathematical ability required for the disciplines is something we can measure and B) the thing we measure is the thing required.

2) Mathematical ability so measured is correlated with participation.

Neither of those propositions are true, as demonstracted by work for NBER by Catherine Weinberger. Her study looked followed high school seniors from 1972 and 1980 through college to correlate mathematical performance with later participation in an EMS discipline.

This study uses data from nationally representative samples of 1972 and 1980 high school seniors, followed longitudinally through the college years to answer the following questions: Is the EMS participation of young women similar to that of young men with the same ability? and: Did most of the men who pursued EMS careers have very high mathematics test scores, or unobserved ability, as high school seniors?

Here is a brief summary of the main point of that paper:

* The level of EMS attainment by women is less than that of men, in line with Census data:

Among 1972 high school seniors, 4.5% of the men and 0.9% of the women graduated college with an EMS major by the 1979 resurvey. Among 1980 high school seniors, 5.8% of the men and 1.8% of the women completed EMS degrees by the 1986 resurvey.

* The numbers of women at the upper tail of the mathematical distribution is less than that of men for both the entire sample and the subset of bachelor's degree graduates:

I now turn to the question of whether EMS participants are drawn from the extreme upper tail of the math score distribution...Figure 3 shows what we already know: there are more men than women at the upper tail of the math score distribution. Figure 4 shows that this is also true within the (more highly selected) group of college graduates. But, within the even more highly selected group of EMS college graduates, the distributions of men's and women's math test scores are much more similar (Figure 5). In fact, among EMS graduates in both cohorts, the women have a higher mean math score and smaller variance than the men. Note that if the relationship between mathematics test scores and EMS participation were the same for men and women, then female EMS participants, drawn from a lower test score distribution, would tend to have lower average scores than male EMS participants. The finding that the mathematics test scores of white women with EMS degrees are not lower than those of the men suggests that women are morecautious about entering unless they have very high scores. (Citations have been removed. Emphasis mine.)

* Here is where it gets interesting. The levels of math achievement for those males that ended up in the EMS discipline were not espcecially high, and by no means prerequisite:

Among all white male 1972 high school seniors employed in the 1979 workforce, only 6% had high school SAT-M[ath] scores greater than 650, while 76% had scores no greater than 550. Although men with high scores are overrepresented in the EMS workforce, they are not the majority. No more than 25% of the EMS workforce had scores above 650. High scores were somewhat more common in the college-educated EMS workforce. Among college graduates employed in EMS occupations, 29% had high scores as high school seniors. Further restricting attention to those who earned an EMS bachelor's degree by 1979 and were employed in an EMS occupation in either 1979 or 1986 did little to change the estimate. Although this group would include those who attended graduate school before entering the EMS workforce, no more than 30% had scores above 650, while 32% had scores no greater than the average humanities major. These estimates lead to the surprising conclusion that less than one-third of the EMS work force had SAT-math scores above the threshold previously presumed in the economics and cognitive psychology literatures. (Citations have been removed. Emphasis mine.)

It would appear that the imputed threshold is not nearly the price of admission that some people would argue. Either we are not measuring the mathematical acumen that is required, or it is not as required as we think.

* Some people might argue with the above point that "Hey, well those people who do poorly at math are probably not being as good a physicist right? Maybe they just got a degree but they are not any good at it." Well, Weinbeger shows that if you look at the math scores compared with later earnings, the individuals with low math scores are doing just as well:

The result that the lowest scoring EMS graduates enjoy the same economic returns as graduates with high scores is extremely robust. This finding suggests that many individuals with lower ability, as measured by the SAT-M[ath], are able to complete college level coursework in EMS subjects, and to enjoy the associated wage premium.

Granted this isn't a direct measure like publishing frequency of working physicists, but considering that this is fundamentally an economic issue I think it is a good proxy for success.

The boldings are to help you skim the long quote above if you wish to do so, to summarize what is important in this quote: that high mathematics SAT scores don't seem to be the prerequisite Tierney thinks they are and that the women who enter science and engineering are already a preselected group. The latter fact is quite important in understanding where Tierney's arguments fail.

What about the idea that women don't want to do science and engineering? The anecdote Tierney gave is one way of looking for answers to that question. Another might be to ask female students who are considering taking science and engineering classes. What might stop them from taking those classes, assuming that they already have interest in the topics? One such thing would certainly be any fear of sexual harassment or discrimination or being subject to hints about the pink girlbrain and so on. Note that I'm not arguing here that such experiences would be any more likely in sciences or engineering (though they might be), only that what we "like" to do is not just based on some biologically determined difference in the tastes of girls and boys. We also take into account all the other information we hear and we weigh all these factors before making a decision. This means that it's tricky to talk about what women "like" to study. Our preferences do depend on the environment we expect to face.

I remember a television program before the Afghanistan war in which young Afghani girls were asked what they would like to become if they could go to school. The most common occupational choice was engineering in that small group, followed by medicine. Do Afghan girls like different things than girls in the United States? Or do our cultures have different ideas of what is suitable for girls to like?

Then there is the whole question of discrimination which Tierney condenses to the idea that women asking to be tenured have the same probability of being accepted as men asking to be tenured. Anyone who has worked in academia knows that if discrimination against women exists it is certainly not limited to the tenure point.

The way these things work is gradually: First, the woman in question must live with the low level campaign of making her life more difficult. She gets assigned the largest and most tiresome classes, the worst equipped laboratories, the least promising graduate students, the most boring and time-consuming committees. Second, her annual evaluations will not be good, almost independently of what she has actually achieved. Third, all these things tell even a thick-skinned and oblivious female scientist that she will not get tenure if she applies for it and the odds are fairly good that she will not apply. Indeed, the cases of clear discrimination in the tenure decision are pretty unusual, because an efficient system of discrimination would have taken care of the problem worker much earlier.

What else could I say about Tierney's column? Perhaps that in his world there are no children at all. I'm sure the report he so aptly summarized said something about the difficulties female scientists and engineers have in a system which focuses most of its professional scrutiny to the same years which are crucial for childbearing. In Tierney's world sex differences in cognition are important but the most obvious sex difference of all is ignored.
I also wanted to talk about the accusation of bias in the formation of the committee, but I have to first find out how the committee is created. If it is a voluntary one, based on interest in the topic, the implications are different than if it is a committee formed in some other way.