C&EN: PERSPECTIVE- REFUTING THE LEAKY PIPELINE HYPOTHESIS

It's been called the leaky pipeline. The path from a bachelor's degree in science to a faculty position notoriously loses women every step of the way. Last year, C&EN's survey of women tenure-track faculty at the top 50 chemistry departments found that women accounted for only 10% of the faculty. This year's survey (C&EN, Oct.1, page 98) finds that the percentage of women holding faculty positions increased only from 10% to 11%.

PHOTO BY MAHLON LOVETT/PRINCETON UNIVERSITY

SURVEY METHODOLOGIES

The National Science Foundation's SURVEY OF GRADUATE STUDENTS AND POSTDOCTORATES IN SCIENCE AND ENGINEERING collects data annually from all institutions offering graduate programs in any science, engineering, or health field. Data items on graduate students, including data on first-time students, are collected at the departmental level at each institution. Information is collected for the fall of the year for which data are being collected. Collection typically ends in July of the following year.

NSF's SURVEY OF EARNED DOCTORATES obtains data on the number and characteristics of individuals receiving research doctoral degrees from U.S. institutions. The survey is mailed to institutional coordinators at graduate schools, who then distribute the forms to individuals receiving a research doctorate. The degree holders are responsible for filling out the forms and returning them to the coordinator, who in turn sends them back to NSF. According to NSF, the estimated response rate is 92%.

The low numbers of women holding faculty positions at top research universities raise many questions about the status of women in academia. How are women faring in graduate school? How many women earn their Ph.D.s? Of those, how many are hired into tenure-track faculty positions? Are the hiring patterns for chemistry also observed in fields such as chemical engineering, electrical engineering, and physics? Where and why is the pipeline leaking?

Tackling these issues requires some calculations. First, I calculated women's success rate in graduate school, which I call "yield," by dividing the number of doctorates earned by women by the number of first-time, full-time female graduate students. I ascertained from the National Science Foundation the number of first-time, full-time graduate students from 1988 to 1992 and the number of doctorates earned from 1994 to 1998. I then calculated the yields for each of the top 24 universities according to National Research Council (NRC) rankings in the fields of chemistry, chemical engineering, electrical engineering, materials science, and physics.

All of the NRC top-ranked schools, except for the University of California, San Francisco, can be found on the NSF's 1998 and 1999 lists of the top 50 university supporters of chemical research, albeit with different rankings. NRC ranked UC San Francisco 23rd on its list of top-ranked chemistry departments. However, because UC San Francisco is considered a specialty graduate school and is not listed in the American Chemical Society's "Directory of Graduate Research," it was not included in this study.

Next, in order to compare women's progress with men's, I devised a parity index by dividing the yield of female doctorates by the yield of male doctorates.

ANALYSIS OF these calculations showed a very large variation in the performance of women. In fact, many of the results contradict widely held beliefs about the state of women in academia today. At the top 24 universities, the yield of female chemists varied from 38 to 85%, with an average yield of 62%. The parity index varied from 0.59 to 1.12; its average was 0.85.

The average yield of female chemists in the top 10 ranked schools was 69%. This is higher than the average yield for the top 24 universities of 62% and significantly higher than the average yield of 57% for the institutions ranked 11 through 24 and the 43% determined for the remaining schools in the NRC top 50. It is assumed that women's chances of success are better at lower ranked universities. However, these numbers indicate that women at top schools are more successful than those attending lower ranked schools. The same trend holds for parity index values. The top 10 ranked schools had an average parity index of 0.89, whereas the average for the universities ranked 11 through 24 and the remaining schools was 0.83 and 0.70, respectively.

With such variance in completion of a doctorate for women chemists, other disciplines were researched as well. Statistics from the fields of chemical engineering, electrical engineering, and physics show similar parity indexes. Materials science has many schools with the number of doctorates awarded significantly greater than that of incoming graduate students, so those data were not used in this comparison. The yields for the engineering disciplines, however, were much lower. I attributed this to the fact that master's degrees in these areas are considered terminal degrees for professionals. Of the four disciplines, physics and chemistry showed the most similarities. It should be noted that the average yield of female physicists at the top 10 ranked universities was 79%, 10 points higher than that for female chemists at the top 10 ranked schools.

After graduating, where do these new Ph.D.s go? How many of the available women chemists are hired by Ph.D.-granting institutions? As C&EN's survey shows, women account for only 11% of the tenure-track faculty at the top 50 universities for the 2001–02 academic year. This dismal number is often rationalized by the claim that the pool of women Ph.D.s is too small. The solution, it is reasoned, is to increase the pool size of women. However, NSF data show that the number of doctorates earned by women chemists for 1970–98 was four times greater than the number awarded to women physicists, yet the number of women chemists and physicists in tenure-track positions at Ph.D.-granting institutions in 1999 was roughly the same.

A related argument is that, although there are women with doctorates, their degrees have not been conferred by the highly ranked schools. Therefore, the pool of women qualified for positions on these faculties is too small. To approach these questions, I determined the number of assistant professors at the top 10 ranked universities by contacting each school. Only assistant professors were chosen because I felt that the most recent hires best reflected the current thinking of department heads. For the pool of candidates, I chose only students with Ph.D.s awarded by these top 10 ranked schools between 1988 and 1992. I used the pool of doctorates from those schools because 76% of the male and female assistant professors at the top 10 ranked schools had received their Ph.D.s from those same schools.

Although 364 chemistry doctorates were awarded to female candidates, only eight of the assistant professors hired (out of a total of 49) at the top 10 ranked universities were women. Furthermore, although the distribution of women in the Ph.D. pool was 22%, only 16% of assistant professors were female.

ALONE, THESE NUMBERS may be surprising, but their disturbing aspect becomes more obvious when compared with the same calculations for physics. Using the same criteria, 18% of assistant professors in the physics departments of top 10 universities were female. This percentage of female hiring was achieved even though the pool distribution for women was 11% and the number of women in the physics pool was only 40% of that for chemistry. Clearly, the pool of talent in chemistry is sufficient, but it remains underutilized.

Of the five disciplines studied, chemistry had the highest percentage of women in the Ph.D. pool. Materials science placed second with 20%. Chemical engineering was third with 16%, while physics and electrical engineering were fourth and fifth with 11% and 7%, respectively. In every field except chemistry, the percentage of women assistant professors is higher than the percentage of women in the available Ph.D. pool.

These studies raise a number of questions. What practices or policies are enabling women to earn doctorates? Why is the hiring in chemistry by the top 10 schools so low when the pool size for women is so large? What have the schools in the other fields done to increase their rate of hiring women? Are the demands placed on chemistry professors different from the other fields, and are those demands making the positions less attractive to women? Are women opting out of applying for academic positions at the top-ranked universities, and, if so, why?

In the next decade, many faculty members will be retiring and new women chemists will earn their Ph.D.s. Significant changes must be made in chemistry department hiring practices for the composition of the faculty to more closely reflect that of the student body.

Falling behind
Percentage of female assistant chemistry professors falls short of their share of the talent pool

PH.D .ASSISTANT

RECIPIENTS, 1988-92 PROFESSORS, 2000

FEMALE % FEMALE TOTAL FEMALE % FEMALE

Chemistry 364 21.6% 49 8 16.3%

Chemical engineering 129 16.2 34 9 26.4

Electrical engineering 125 7.2 89 11 12.3

Materials science 118 19.7 32 7 21.9

Physics 138 10.7 61 11 18.0

NOTE: Assistant professors employed by the departments ranked as the top 10 by the National Research Council. SOURCES: National Science Foundation Survey of Graduate Students and Postdoctorates in Science and Engineering, Public Use Data Tables; WebCASPAR Database System; C&EN; author's survey

Top

Leaky pipeline
Women graduate students tread a rockier path than their male counterparts on the way to a Ph.D.

NRC FIRST-YEAR GRADUATE STUDENTS1988–92 DOCTORATES
1994–98 % YIELD PARITY

RANKING FEMALE MALE FEMALE MALE FEMALE MALE INDEX

1 U of California, Berkeley 96 245 65 195 67.7% 79.6% 0.85

2 California Inst. of Technology 62 164 34 113 54.8 68.9 0.80

3 Harvard U 33 132 24 109 72.7 82.6 0.88

4 Stanford U 67 154 44 109 65.7 70.8 0.93

5 Mass. Inst. of Technology 68 172 44 111 64.7 64.5 1.00

6 Cornell U 64 126 53 110 82.8 87.3 0.95

7 Columbia U 41 93 31 70 75.6 75.3 1.00

8 U of Illinois, Urbana-Champaign 84 210 36 149 42.9 71.0 0.60

9 U of Wisconsin, Madison 75 184 56 168 74.7 91.3 0.82

10 U of Chicago 34 90 29 74 85.3 82.2 1.04

11 U of California, Los Angeles 96 165 46 90 47.9 54.5 0.88

12 Yale U 63 92 36 64 57.1 69.6 0.82

13 U of Texas, Austin 92 184 44 117 47.8 63.6 0.75

14 Northwestern U 69 100 44 70 63.8 70.0 0.91

15 Texas A&M U, College Station 130 233 60 144 46.2 61.8 0.75

16 Indiana U, Bloomington 81 149 31 90 38.3 60.4 0.63

17 U of North Carolina, Chapel Hill 96 158 73 108 76.0 68.4 1.11

18 U of California, San Diego 73 110 31 58 42.5 52.7 0.81

19 Penn. State U, University Park 88 138 50 112 56.8 81.2 0.70

20 Princeton U 46 83 38 61 82.6 73.5 1.12

21 U of Minnesota, Minneapolis 77 163 59 122 76.6 74.8 1.02

22 Ohio State U, Columbus 81 229 41 144 50.6 62.9 0.80

24 Purdue U 112 186 77 187 68.8 100.5 0.68

25 U of Pennsylvania 81 109 32 73 39.5 67.0 0.59

TOTAL 1,809 3,669 1,078 2,648 59.6%^a 72.2%^a 0.83^a

NOTE: The National Research Council ranked UC San Francisco 23rd on its list of top-ranked chemistry departments. However, because it is a specialty graduate school, it is not included in this survey. a Calculated from totals. " SOURCES: National Science Foundation Survey of Graduate Students and Postdoctorates in Science and Engineering, Public Use Data Tables; WebCASPAR Database System

Valerie Kuck recently retired from Lucent Technologies, Murray Hill, N.J. C&EN summer intern Allison Byrum also contributed to this story.

I am grateful to Joan Burelli of NSF for the data on the graduate schools and the doctorates and to Michael Schabel of Lucent Technologies and Amaliya Jurta of the National Academy of Sciences for determining the composition of the faculties in chemical engineering, electrical engineering, materials science, and physics.