American policy analysts are concerned about the declining US share in world patenting and scientific publishing. Many trace to the perceived failure of the US to educate as many scientists and engineers as “competitor” countries.
One possible solution to this problem is to increase skilled immigration in science and engineering. An alternative is to increase the number of natives in science and engineering, with the under-represented groups of women and minorities as obvious targets.
The National Academy of Sciences (2007) and the Institute of Electrical and Electronics Engineers - USA (2007) recommend both immigration-based solutions and domestic solutions such as better primary and secondary education, more public research funding, and special scholarships to encourage natives to study science and engineering. Hewlett et al. (2008) emphasise another strategy: increased retention of women in science and engineering. They identify reasons why women leave science and engineering at a higher rate than men, and propose ways to make science and engineering careers more “friendly” to women.
If women leave science and engineering at disproportionate rates, this could be an indicator of inefficiency, supporting the contention that the US has too few scientists and engineers. Certain practices in science and engineering firms may prevent women from reaching their full potential, or there may be outright discrimination against women in such firms. The existence of such practices or discrimination could in turn discourage women from entering science and engineering in the first place.
In my recent work (Hunt 2010), I investigate whether female exits from science and engineering are disproportionate compared to other fields and why this might be. I also consider whether high female exits are simply a hallmark of male-dominated fields generally, rather than of science and engineering specifically.
The importance of comparing science and engineering with other fields
My use of non-science and engineering fields as a comparison group is a departure from earlier studies. The considerable literature on women leaving science and engineering highlights the difficulty of balancing long work hours and family in science and engineering, the isolation of being a minority and the associated lack of mentoring and networks, the risk-taking environment, the “hostile macho culture” and discrimination (see Hall 2007; Hewlett et al. 2008; Preston 1994, 2004, 2006; Sonnert and Holton 1995; and Stephan and Levin 2005). With the exception of Morgan (2000) however, as far as I am aware the research uses samples of current or former scientists and engineers only, without any comparison with other skilled occupations.
To see the limitations of such a focus, consider a common explanation for women quitting science and engineering, i.e. long work hours. Long work hours may indeed disproportionately lead women rather than men to leave science and engineering, but long work hours may also disproportionately lead skilled women to leave other fields. Women may simply churn more than men in search of a job with optimal work hours. Thus, while it may be worthwhile for science and engineering employers to implement Hewlett et al. (2008)'s prescription of more flexible working time, if other employers implement and benefit from similar policies, any science and engineering-specific disadvantage in retaining women will persist.
If women do leave science and engineering disproportionately compared to other fields, it is useful to know whether this is merely symptomatic of all male-dominated fields. If this is the case, explanations related to the specific technical nature of science and engineering work can be eliminated.
Data and results
I use the 1993 and 2003 National Surveys of College Graduates, defining a worker as having left his or her field if he or she reports doing work unrelated to the field of study of the highest degree, or is not employed. Respondents doing unrelated work are asked why they are working outside their field of study. All workers are asked what importance they attach to various job characteristics such as pay, promotion, and location, allowing me to control for possible gender differences in such tastes by field of study, as well as for experience, education, and other characteristics.
I demonstrate that the exit rate for women compared to men is indeed higher from science and engineering than from other fields. I show that the gap in exits is concentrated more in engineering than in science, and in exits to other fields rather than to non-employment.
Furthermore, I show that the problems are not those emphasised by the previous literature. Instead I find that the most important driver of excess female exits from engineering is dissatisfaction over pay and promotion opportunities, a factor explaining about 60% of the differential gender gap in exit rates. Concerns about pay and promotion have gone unnoticed by the literature studying only science and engineering fields, because women are slightly less likely to leave engineering for this reason than men – but women are much less likely than men to leave non-science and engineering fields for this reason.
Family-related constraints are not a factor – while many more women than men cite family issues as the reason for leaving engineering, the gender gap is as large in non-science and engineering fields. I find that working conditions, the unavailability of a job in the field, changes in professional interests and job location play statistically significant but minor roles. I do find slight excess exits of women from science for family-related reasons but these are offset by relatively lower female exits for all other reasons.
I find that the gap between the female and male exit rates from a field is strongly positively related to the share of men who studied the field. Figure 1 shows that the relationship is fairly linear, and that if engineering fields have the highest female excess exits, it is because they have the highest share of men. The share of men is also sufficient to explain the excess female exits for pay and promotion reasons. I investigate whether the male share is proxying for the field's working hours, wages, or share of workers in management, which are all positively correlated with the male share, and find this is not the case.
Figure 1. Excess female exits from fields of study by share of men in field
The results show that the high share of male workers and women’s concerns about pay and promotion opportunities are key factors in the excess female exit rates from engineering. This suggests that a lack of mentoring and networks, or discrimination by managers and co-workers are the more promising of the existing explanations for excess female exits from engineering. Explanations hinging on the precise nature of engineering work should be discarded. Instead remedies should be applied to all fields with a high share of male workers.
Hall, Linley Erin (2007), Who's Afraid of Marie Curie? The Challenges Facing Women in Science and Technology, Emeryville, CA, Seal Press.
Hewlett, Sylvia Ann, Carolyn Buck Luce, and Lisa J Servon (2008), “The Athena Factor: Reversing the Brain Drain in Science, Engineering, and Technology”, Harvard Business Review Research Report 10094.
Hunt, Jennifer (2010), “Why Do Women Leave Science and Engineering?”, NBER Working Paper 15853.
Institute of Electrical and Electronics Engineers-USA (2007), “Ensuring a Strong High-Tech Workforce Through Educational and Employment-Based Immigration Reforms”.
Morgan, Laurie A (2000), “Is Engineering Hostile to Women? An Analysis of Data from the 1993 National Survey of College Graduates”, American Sociological Review, 65(2):316-321.
National Academy of Sciences, National Academy of Engineering and Institute of Medicine (2007), Rising Above the Gathering Storm: Energizing and Employing America for a Brighter Future, The National Academies Press.
Preston, Anne E (1994), “Why Have All the Women Gone? A Study of Exit of Women from the Science and Engineering Professions”, American Economic Review, 84:1446-1462.
Preston, Anne E (2004), Leaving Science: Occupational Exit from Science Careers, Russell Sage Foundation.
Preston, Anne E (2006), “Women Leaving Science”, Haverford College working paper.
Sonnert, Gerhard and Gerald Holton (1995), Gender Differences in Science Careers, Rutgers University Press.
Stephan, Paula E and Sharon G Levin (2005), “Leaving Careers in IT: Gender Differences in Retention”, Journal of Technology Transfer, 30:383-396.