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Suggested Citation:"4: Labor Force Participation." National Research Council. 2001. From Scarcity to Visibility: Gender Differences in the Careers of Doctoral Scientists and Engineers. Washington, DC: The National Academies Press. doi: 10.17226/5363.
×

4
Labor Force Participation

The Attrition of Women from the S&E Labor Force

…receipt of a doctorate in S&E does not imply full participation in these fields.

—J.Scott Long and Mary Frank Fox, Annual Review of Sociology, 1995.1

INTRODUCTION

Increases in the number of women among new Ph.D.s do not translate directly into increases in the proportion of women in the science and engineering labor force. Each new cohort of Ph.D.s represents only a small fraction of the total number of scientists and engineers. This is shown in Figure 4–1, which compares the growth in the percent of women among new Ph.D.s, to increases in the labor force, and finally among those employed full time in S&E. The proportion of women among new Ph.D.s, shown by the darkest bars, increased by 20 percentage points from 13 percent in 1973 to 33 percent in 1995, while the proportion of women in the labor force increased more slowly from 8 percent in 1973 to 21 percent in 1995. The proportion of women in the S&E labor force must increase slowly as older, predominantly male cohorts retire and are replaced by new cohorts that have a greater proportion of women. Hargens and Long (2000) demonstrate how demographic factors, such as the gender composition of new cohorts and the age distribution of currently employed

1  

Long and Fox (1995).

Suggested Citation:"4: Labor Force Participation." National Research Council. 2001. From Scarcity to Visibility: Gender Differences in the Careers of Doctoral Scientists and Engineers. Washington, DC: The National Academies Press. doi: 10.17226/5363.
×

FIGURE 4–1 The percent of women among new Ph.D.s, among all scientists and engineers available to work in science and engineering, and among those working full time, by year of survey. NOTE: Labor force includes those who are not employed or working part time.

scientists, limit the rate of change in the gender composition of the academic labor force. For example, even if women were three-fourths of the new Ph.D.s, it would take decades before gender parity would be achieved in the labor force. Obviously, with women making up far less than half of the new Ph.D.s, changes will be even slower.

Second, after completion of the doctorate, a greater proportion of women than men do not attain full-time careers in science and engineering. While doctoral scientists and engineers have low rates of unemployment compared to the total U.S. labor force, women with doctorates are substantially more likely than men to be unemployed, employed part time, employed outside of S&E, or not be in the labor force. This is reflected by the white bars in Figure 4–1, which show that the percent of full-time workers in S&E who are women increased from 6.5 percent to 20 percent. Differences between men and women in labor force participation add up to less accumulated work experience and less valuable experience for women over the course of their careers, a factor that is important for understanding the gender differences in career outcomes that are described in later chapters.

This chapter begins by examining the sex composition of the scientific

Suggested Citation:"4: Labor Force Participation." National Research Council. 2001. From Scarcity to Visibility: Gender Differences in the Careers of Doctoral Scientists and Engineers. Washington, DC: The National Academies Press. doi: 10.17226/5363.
×

and engineering labor force in our five broad fields. How do men and women differ in the percent who are working full time in S&E occupations? Of those Ph.D.s who are not working full time in S&E, are they working outside of science, working part time, unemployed and looking for work, or out of the labor force? We find that while there has been improvement since 1973, female Ph.D.s continue to be substantially less likely than men to be fully employed in scientific and engineering occupations. Second, we examine the reasons given by scientists and engineers for working part time and look at characteristics of scientists that are associated with less than full employment. We find that lack of full participation for women is most strongly related to familial status. Finally, we summarize the effects of the underemployment of women by comparing the average number of years of professional experience for men and women. Overall during the past 20 years, 10 percent of the potential professional work of female doctorates has been lost as a result of women being less likely to be fully employed.

Before proceeding, it is important to emphasize that participation in the full time scientific and engineering labor force includes a variety of jobs that differ greatly in prestige, security, and remuneration. This chapter considers only the question of whether a Ph.D. scientist is working full time in S&E, not the equally important question of what kind of work. In later chapters, we consider only those scientists and engineers with full-time employment in S&E and explore differences between men and women in sector of employment, work activity, position, and salary.

A Note on Terminology

Before proceeding, it is helpful to define several terms that are used in this chapter.

  • Labor force is defined as Ph.D.s in S&E fields who are living in the United States and are under the age of 75. The labor force includes both part time workers and those who are unemployed.

  • Full-time labor force is defined as members of the labor force who are working full time in some area of science or engineering.

  • Employed outside of S&E includes doctoral scientists and engineers who are working full time in occupations that are not directly related to S&E as defined by the Survey of Doctorate Recipients.

  • Unemployed includes those without jobs who are seeking work.

  • Out of the labor force are those who are not working and not seeking work.

  • Underemployment includes part time workers and the unemployed.

Suggested Citation:"4: Labor Force Participation." National Research Council. 2001. From Scarcity to Visibility: Gender Differences in the Careers of Doctoral Scientists and Engineers. Washington, DC: The National Academies Press. doi: 10.17226/5363.
×

THE FULL-TIME SCIENTIFIC AND ENGINEERING LABOR FORCE2

As the growth in the production of new Ph.D.s slowed since 1973, the full labor force of Ph.D. scientists and engineers increased 220 percent from 187,236 in 1973 to 412,497 in 1995. During this period, the entry of increasingly female cohorts gradually changed the gender composition of the full-time labor force, from 6.5 percent female in 1973 to 19.6 percent in 1995 (Figure 4–2). But, as documented in the last chapter, the proportion of female Ph.D.s differs widely by field, which affects the sex composition of the full-time labor force within fields. While there has been substantial movement towards parity, the full-time participation of women in the labor force remains far below 50 percent in all fields.

Engineering: While the number of male Ph.D. engineers working full time doubled from 30,208 in 1973 to 69,013 in 1995, the corresponding number of women increased by a factor of 40, from a mere 82 in 1973 to 3,589 in 1995. Still, by 1995 women were only 5 percent of the full-time labor force. As shown in Table 4–1, in 1995 women were least represented in the largest subfields of electrical and chemical engineering, and were most strongly represented in the smaller fields of industrial engineering with 15 percent women and materials sciences with 10 percent women.

FIGURE 4–2 The percentage of the full-time scientific and engineering labor force that is female, by field and year of survey.

2  

See Appendix Tables B-1 and B-2 for additional data.

Suggested Citation:"4: Labor Force Participation." National Research Council. 2001. From Scarcity to Visibility: Gender Differences in the Careers of Doctoral Scientists and Engineers. Washington, DC: The National Academies Press. doi: 10.17226/5363.
×

Mathematical Sciences: The number of female doctoral mathematicians working full time in S&E grew from 677 in 1973 to 3,728 in 1995. This increase of 450 percent can be compared to a 121 percent increase in male mathematicians from 11,639 in 1973 to 25,711 in 1995. Overall, women represented 5.5 percent of the mathematicians in 1973, which increased to 13 percent in 1995. As shown in Table 4–2, in 1995 women were most strongly represented in statistics and probability with 18 percent of the full-time labor force and in the rapidly growing field of computer science where they were 13 percent.

Physical Sciences. The proportional representation of women in the physical sciences is similar to that in mathematics. In 1973, there were 1,637 women, which corresponded to 3 percent of the total Ph.D.s in the physical sciences working full time in S&E. By 1995 the number of women increased by 480 percent to 9,505 or 10.5 percent of the full-time labor force. During this same period, the number of male physical scientists increased only 50 percent from 52,168 in 1973 to 81,373 in 1995. As shown in Table 4–3, the largest increases overall, as well as for women, were in the large subfields of physics and chemistry, which represented 31 percent and 51 percent of the full time Ph.D.s in 1995, respectively. The largest proportional representation of women is in chemistry, which grew from being 4 percent female in 1973 to 14 percent female in 1995. While the second largest number of women is in physics, with nearly 1,500 women in 1995, the growth was from a mere 1.3 percent of the full-time Ph.D. labor force being female in 1973 to a still small 5 percent in 1995.

Life Sciences: Overall, women have a larger representation in the full-time labor force in the life sciences than the preceding broad fields. In 1973, there were 4,598 women, 9.5 percent of the total, compared to 44,053 men. The proportion of women increased to 26 percent in 1995, as the number of women grew six fold to 29,885, while the number of men only doubled to 85,098. As shown in Table 4–4, women are found most often in the subfield of biological sciences, where they were 49 percent of the full-time labor force in 1995. They were least represented in the agricultural sciences with only 1 percent of the total in 1973, increasing to 12 percent in 1995.

Social and Behavioral Sciences. Women are most highly represented in the social and behavioral sciences. As the number of Ph.D.s working full time increased 150 percent from 43,298 in 1973 to 107,216 in 1995, the representation of women grew from 12 percent to 33 percent. As shown in Table 4–5, women are most highly represented in anthropology with 40 percent of the full-time labor force, followed by 39 percent in the large

Suggested Citation:"4: Labor Force Participation." National Research Council. 2001. From Scarcity to Visibility: Gender Differences in the Careers of Doctoral Scientists and Engineers. Washington, DC: The National Academies Press. doi: 10.17226/5363.
×

TABLE 4–1 Numbers of Engineers Working Full Time in S&E, by Sex, Subfield, and Year of Survey

 

1973

1979

#

Men

#

Women

%

Women

#

Men

#

Women

%

Women

Biomedical

307

2

0.6

778

10

1.3

Chemical

4,835

13

0.3

6,696

33

0.5

Electrical

7,317

17

0.2

9,578

53

0.6

Industrial

720

4

0.6

1,007

12

1.2

Materials Science

146

0

0.0

599

12

2.0

Other

16,883

46

0.3

23,860

218

0.9

Total

30,208

82

0.3

42,518

338

0.8

TABLE 4–2 Numbers of Mathematicians Working Full Time in S&E, by Sex, Subfield, and Year of Survey

 

1973

1979

#

Men

#

Women

%

Women

#

Men

#

Women

%

Women

Computer Science

540

30

5.3

1,330

92

6.5

Probability and Statistics

2,233

130

5.5

3,710

318

7.9

Mathematics

8,866

517

5.5

10,871

780

6.7

Total

11,639

677

5.5

15,911

1,190

7.0

TABLE 4–3 Numbers of Physical Scientists Working Full Time in S&E, by Sex, Subfield, and Year of Survey

 

1973

1979

#

Men

#

Women

%

Women

#

Men

#

Women

%

Women

Astronomy

930

64

6.4

1,531

89

5.5

Physics

16,424

220

1.3

20,603

427

2.0

Chemistry

28,936

1,236

4.1

34,990

2,105

5.7

Oceanography

523

6

1.1

888

37

4.0

Geosciences

5,355

111

2.0

7,287

292

3.9

Total

52,168

1,637

3.0

65,299

2,950

4.3

Suggested Citation:"4: Labor Force Participation." National Research Council. 2001. From Scarcity to Visibility: Gender Differences in the Careers of Doctoral Scientists and Engineers. Washington, DC: The National Academies Press. doi: 10.17226/5363.
×

1989

1995

#

Men

#

Women

%

Women

#

Men

#

Women

%

Women

1,314

84

6.0

1,729

135

7.2

9,410

257

2.7

9,574

504

5.0

12,595

213

1.7

16,422

601

3.5

901

75

7.7

1,590

279

14.9

1,587

138

8.0

3,304

366

10.0

32,631

791

2.4

36,394

1,704

4.5

58,438

1,558

2.6

69,013

3,589

4.9

1989

1995

#

Men

#

Women

%

Women

#

Men

#

Women

%

Women

3,670

397

9.8

6,501

933

12.6

5,067

798

13.6

5,165

1,175

18.5

13,610

1,304

8.7

14,045

1,620

10.3

22,347

2,499

10.1

25,711

3,728

12.7

1989

1995

#

Men

#

Women

%

Women

#

Men

#

Women

%

Women

2,310

175

7.0

2,578

202

7.3

25,577

982

3.7

26,977

1,473

5.2

39,788

4,426

10.0

39,773

6,251

13.6

1,336

132

9.0

1,537

212

12.1

9,857

809

7.6

10,508

1,367

11.5

78,868

6,524

7.6

81,373

9,505

10.5

Suggested Citation:"4: Labor Force Participation." National Research Council. 2001. From Scarcity to Visibility: Gender Differences in the Careers of Doctoral Scientists and Engineers. Washington, DC: The National Academies Press. doi: 10.17226/5363.
×

TABLE 4–4 Numbers of Life Scientists Working Full Time in S&E, by Sex, Subfield, and Year of Survey

 

1973

1979

#

Men

#

Women

%

Women

#

Men

#

Women

%

Women

Agricultural

8,766

86

1.0

12,093

297

2.4

Medical

30,916

4,131

11.8

41,403

7,218

14.8

Biological

4,371

381

8.0

6,724

1,078

13.8

Total

44,053

4,598

9.5

60,220

8,593

12.5

TABLE 4–5 Numbers of Social and Behavioral Scientists Working Full Time, by Sex, Subfield, and Year of Survey

 

1973

1979

#

Men

#

Women

%

Women

#

Men

#

Women

%

Women

Psychology

16,048

3,060

16.0

24,690

7,005

22.1

Anthropology

1,226

246

16.7

2,193

756

25.6

Economics

7,359

376

4.9

9,261

781

7.8

Sociology

4,018

753

15.8

5,649

1,592

22.0

Other

9,434

778

7.6

14,058

1,820

11.5

Total

38,085

5,213

12.0

55,851

11,954

17.6

field of psychology and 36 percent in sociology. Women were least represented in the more mathematical field of economics, where they grew from 5 percent of the full-time labor force in 1973 to 15 percent in 1995.

THE AGE STRUCTURE IN SCIENCE AND ENGINEERING

The later entry of women into S&E is reflected in their younger professional age. Professional age is important for understanding career outcomes since years working in the profession affect the positions that scientists and engineers hold. For example, tenure and promotion in academia are related to the time a person has been in rank. If the average female faculty member is younger than the average male, proportionately fewer women would be full professors, all else being equal. Administrative positions and appointment to gatekeeping roles (e.g., editor of a journal) are also associated with age, with older scientists being more likely to

Suggested Citation:"4: Labor Force Participation." National Research Council. 2001. From Scarcity to Visibility: Gender Differences in the Careers of Doctoral Scientists and Engineers. Washington, DC: The National Academies Press. doi: 10.17226/5363.
×

1989

1995

#

Men

#

Women

%

Women

#

Men

#

Women

%

Women

15,569

1,354

8.0

15,688

2,053

11.6

54,025

14,699

21.4

63,815

22,452

26.0

11,490

4,955

30.1

5,595

5,380

49.0

81,084

21,008

20.6

85,098

29,885

26.0

1989

1995

#

Men

#

Women

%

Women

#

Men

#

Women

%

Women

34,961

16,818

32.5

36,317

22,833

38.6

2,914

1,441

33.1

3,419

2,283

40.0

11,907

1,654

12.2

11,659

2,063

15.0

6,575

2,717

29.2

6,255

3,536

36.1

18,501

4,251

18.7

14,633

4,218

22.4

74,858

26,881

26.4

72,283

34,933

32.6

hold these influential positions. Zuckerman and Merton (1972) discuss the many ways in which age, aging, and the age structure affect the scientific career.

Age structure is determined by the size of new cohorts of Ph.D.s relative to the size of past cohorts and the rate at which each cohort leaves S&E through retirement, death, and migration to other occupations. If each new cohort were the same size, the age structure would be nearly uniform, with approximately the same number of people at each age until retirement. However, the number of new Ph.D.s grew rapidly after World War II and in response to Sputnik, with slower growth in the 1970s and 1980s. During these periods of slower growth, the proportion of women in each new cohort grew most rapidly. These trends resulted in different age structures for men and women.

Population pyramids are the standard method for examining the age structure in a population. A population pyramid compares the age distri-

Suggested Citation:"4: Labor Force Participation." National Research Council. 2001. From Scarcity to Visibility: Gender Differences in the Careers of Doctoral Scientists and Engineers. Washington, DC: The National Academies Press. doi: 10.17226/5363.
×

TABLE 4–6 Mean Years Since Ph.D., by Field, Sex, and Year of Survey

 

Combined­ Fields

Engineering

Mathematics

Men

Women

Men

Women

Men

Women

1973

11.4

10.0

8.8

7.4

9.9

10.3

1979

12.5

9.3

11.3

6.4

11.6

9.6

1989

15.4

10.4

14.9

7.1

15.3

11.7

1995

16.8

11.4

15.1

7.2

15.8

11.6

 

Physical Sciences

Life Sciences

Social/Behavioral Sciences

Men

Women

Men

Women

Men

Women

1973

13.0

11.4

12.2

10.5

10.8

9.1

1979

14.4

11.4

12.7

10.0

11.4

8.3

1989

16.9

11.5

14.9

10.4

14.8

10.2

1995

18.3

11.3

16.6

11.3

17.2

11.9

butions for two groups by showing the percent of individuals within each group who is a given age. For our purposes, we consider professional age, which is defined as the number of years since the receipt of the doctorate. Panels A and B of Figure 4–3 are population pyramids for male and female scientists and engineers in the S&E labor force in 1973 and 1995. Each figure contains two histograms. The histogram on the left shows the percent of men in each three-year age group; the histogram on the right shows corresponding data for women. Note that the sum of the bars in each histogram will equal 100.

Comparing the plots for men and women in 1973, we see that a greater proportion of women is younger, with a median professional age of seven compared to a median age of nine for men. The shape of the distribution resulted from the proportionately smaller number of women receiving Ph.D.s before 1966 (corresponding to professional age 6), the greater inflow of women after 1965, and the substantial attrition of women who entered S&E before World War II. In 1995, shown in Panel B, the decreasing size of new cohorts of men resulted in an increase in the median professional age of men from 9 to 16. For women, the median age increased only from 7 to 9, since the sizes of new cohorts of women were larger relative to the total number of women in science and engineering. The percent of men at each age 1 through 27 is nearly uniform, while the distribution for women has a triangular shape corresponding to the in

Suggested Citation:"4: Labor Force Participation." National Research Council. 2001. From Scarcity to Visibility: Gender Differences in the Careers of Doctoral Scientists and Engineers. Washington, DC: The National Academies Press. doi: 10.17226/5363.
×

FIGURE 4–3 Distribution of professional ages in the science and engineering labor force, by sex and year. NOTE: Professional age is defined as the number of years since the receipt of the doctorate.

Suggested Citation:"4: Labor Force Participation." National Research Council. 2001. From Scarcity to Visibility: Gender Differences in the Careers of Doctoral Scientists and Engineers. Washington, DC: The National Academies Press. doi: 10.17226/5363.
×

creasing size of newer cohorts. The similarity of the size of age groups 1– 3 and 4–6 for women shows that more recent cohorts of Ph.D.s have been more similar in size.

The five fields differ in the rate at which they are growing and in the proportion of women in new cohorts of Ph.D.s. Consequently, the age structures differ among fields, as shown in Table 4–6. While the average age of men increased in all fields, the greatest aging occurred in the more slowly growing fields of engineering and the social/behavioral sciences. The increase in professional age was smallest in the life sciences where growth of the field was greater in recent years. For women, there was very little aging except in the social and behavioral sciences and, to a lesser extent, the life sciences. Historically, these fields had greater proportions of women, and accordingly the impact of new cohorts of Ph.D.s on the age structure has been less.

LABOR FORCE PARTICIPATION3

While most doctoral scientists and engineers have full-time employment in science and engineering occupations, women are far less likely than men to be fully employed. The attrition of women from the full-time S&E labor force is the focus of this section. We begin by examining levels of full-time employment, before examining the reasons for less than full-time employment of female scientists and engineers.

Full-Time Employment

In 1973, 91 percent of male scientists and engineers were working full time in occupations that are related to their training, while women were 20 points less likely to have full-time employment in S&E. As shown in Table 4–7, since 1973 levels of full-time employment in S&E for men have decreased in all fields with an overall rate of 85 percent in 1995, while rates for women improved by nearly 10 points. While there is some variation across fields, by 1995 gender differences in all fields had been reduced to around 10 points. Still, this is an important difference, representing 1 out of 10 women with a doctorate in science and engineering.

Rates of full-time employment in the social and behavioral sciences are between 5 and 10 points lower than in other fields. Table 4–8 shows that these lower rates are largely the result of a greater percentage of social and behavioral scientists who are working full time in occupations outside of S&E. Such employment includes positions that are either unre-

3  

See Appendix Tables B-3-B-7 for additional data.

Suggested Citation:"4: Labor Force Participation." National Research Council. 2001. From Scarcity to Visibility: Gender Differences in the Careers of Doctoral Scientists and Engineers. Washington, DC: The National Academies Press. doi: 10.17226/5363.
×

TABLE 4–7 Percent of Doctoral Scientists and Engineers with Full-Time Employment Within Science and Engineering, by Sex, Field, and Year of Survey

 

Combined Fields

Engineering

Mathematics

1973

Men

90.9

93.1

94.7

Women

70.9

76.5

Difference

20.0

18.2

1979

Men

89.0

90.9

90.5

Women

74.1

81.8

78.4

Difference

14.9

9.1

12.1

1989

Men

88.1

89.7

91.0

Women

74.4

84.8

80.0

Difference

13.7

4.9

11.0

1995

Men

85.8

90.6

90.8

Women

73.5

81.3

79.5

Difference

12.3

9.3

11.3

 

Physical Sciences

Life Sciences

Social and Behavioral Sciences

1973

Men

89.8

93.3

87.0

Women

64.1

74.4

69.7

Difference

25.7

18.9

17.3

1979

Men

89.7

92.5

83.2

Women

73.2

77.9

71.3

Difference

16.5

14.6

11.9

1989

Men

90.3

91.3

81.0

Women

79.9

80.3

68.5

Difference

10.4

11.0

12.5

1995

Men

87.2

85.3

79.6

Women

77.4

75.9

69.4

Difference

9.8

9.4

10.2

NOTE:—indicates too few cases to compute statistic. Full-time postdoctoral fellows are considered to be employed full time in S&E.

Suggested Citation:"4: Labor Force Participation." National Research Council. 2001. From Scarcity to Visibility: Gender Differences in the Careers of Doctoral Scientists and Engineers. Washington, DC: The National Academies Press. doi: 10.17226/5363.
×

TABLE 4–8 Percent of Doctoral Scientists with Full-Time Employment Outside of Science and Engineering, by Sex, Field, and Year of Survey

 

Combined Fields

Engineering

Mathematics

1973

Men

6.1

4.7

2.9

Women

6.5

4.8

Difference

–0.4

–1.9

1979

Men

7.6

6.0

6.6

 

Women

7.7

7.0

6.4

Difference

–0.1

–1.0

0.2

1989

Men

8.7

7.3

6.8

Women

9.5

8.0

8.0

 

Difference

–0.8

–0.7

–1.2

1995

Men

8.1

4.6

4.2

Women

9.9

4.3

5.0

Difference

–1.8

0.3

–0.8

 

Physical Sciences

Life Sciences

Social and Behavioral Sciences

1973

Men

6.6

3.9

9.8

Women

6.9

4.8

8.1

Difference

–0.3

–0.9

1.7

1979

Men

7.2

4.5

12.5

Women

7.2

4.4

10.1

Difference

0.0

0.1

2.4

1989

Men

6.8

6.0

14.4

Women

7.0

6.7

10.3

Difference

–0.2

–0.7

4.1

1995

Men

6.3

9.1

13.2

Women

8.4

11.1

10.3

Difference

–2.1

–2.0

2.9

NOTE:—indicates too few cases to compute statistic.

Suggested Citation:"4: Labor Force Participation." National Research Council. 2001. From Scarcity to Visibility: Gender Differences in the Careers of Doctoral Scientists and Engineers. Washington, DC: The National Academies Press. doi: 10.17226/5363.
×

lated or indirectly related to a person’s doctoral training. For example, a Ph.D. in engineering could work as a sales person for a company manufacturing computers (a related occupation) or could sell insurance (an unrelated occupation). In the social/behavioral sciences, the percentage of Ph.D.s with full-time employment outside of S&E is between 10 percent and 14 percent, with 2 percent fewer women in such positions. The large percentage working outside of S&E is a result of positions such as a social worker being classified as work outside of S&E; these positions could reasonably be classified as being in S&E. In engineering, mathematics, the physical sciences, and the life sciences, between 3 percent and 10 percent of the Ph.D.s have full-time employment outside of S&E, with only small differences in the percentages for men and women. Overall, there is greater employment outside of S&E in the physical sciences and a recent increase in the life sciences where the rate reached 10 percent in 1995.

As a cohort of scientists ages through the career, there are gradual changes in patterns of full-time employment. Figure 4–4 illustrates these changes by examining the cohort of life scientists who received their degrees in the 1970s. The data from the 1979 survey show employment in the early part of the career; 1989 represents the middle of the career, roughly 15 years after the degree; and 1995 shows labor force status about 20 years after the degree. For both men and women, there is a decrease in

FIGURE 4–4 Change over the career in the percent of life scientists with Ph.D.s from the 1970s who are working full time in science and engineering and outside of science and engineering, by sex, and year of survey.

Suggested Citation:"4: Labor Force Participation." National Research Council. 2001. From Scarcity to Visibility: Gender Differences in the Careers of Doctoral Scientists and Engineers. Washington, DC: The National Academies Press. doi: 10.17226/5363.
×

TABLE 4–9 Percent of Scientists from the 1970 Cohort Who Are Working Full Time in S&E or Outside of S&E, by Sex, Field, and Year of Survey

 

1970 Cohort of Men in

1970 Cohort of Women in

1979

1989

1995

1979

1989

1995

Engineering

In Science

93.0

88.4

87.4

Outside

4.7

8.1

6.9

Total FT

97.7

96.5

94.3

Mathematics

In Science

90.7

91.7

90.0

80.9

80.9

79.4

Outside

6.1

7.0

5.3

4.3

7.8

3.1

Total FT

96.8

98.7

95.3

85.2

88.7

82.5

Physical Sciences

In Science

93.2

89.5

87.5

78.0

78.2

70.2

Outside

4.1

8.1

7.6

7.0

9.7

15.0

Total FT

97.3

97.6

95.1

85.0

87.9

85.2

Life Sciences

In Science

94.4

90.1

84.8

82.4

77.9

73.3

Outside

3.2

7.5

7.6

7.0

4.7

10.5

Total FT

97.6

97.6

92.4

89.4

82.6

83.8

Social and Behavioral Sciences

In Science

84.5

82.3

80.8

72.1

66.1

67.1

Outside

11.5

14.5

14.0

9.4

15.0

12.5

Total FT

96.0

96.8

94.8

81.5

81.1

79.6

NOTE:—indicates that there were too few cases to compute this statistic.

full-time employment in S&E as the career progresses, with gradual increases in the percentage who are working outside of S&E. Combining full-time employment both in and out of S&E, there is a slight decrease in full-time employment as the scientists age. Table 4–9 shows that these overall tendencies in full-time employment hold in other fields with the exception of mathematics where there was a slight increase in employment in 1989. These changes in full-time employment occur as scientists move into part-time employment, become unemployed, or leave the labor force. These forms of underemployment, which represent a significant loss of highly trained individuals, are considered following a shorter discussion of postdoctoral fellowships.

Postdoctoral Fellowships

The postdoctoral fellowship is another form of employment that is increasingly common early in the career. The Committee on a Study of Postdoctorals in Science and Engineering in the United States characterized the critical importance of the postdoctoral fellowship as follows (NRC 1981:1):

Suggested Citation:"4: Labor Force Participation." National Research Council. 2001. From Scarcity to Visibility: Gender Differences in the Careers of Doctoral Scientists and Engineers. Washington, DC: The National Academies Press. doi: 10.17226/5363.
×

For many of the most talented scientists and engineers the postdoctoral appointment has served as an important period of transition between formal education and a career in research. The appointment has provided recent doctorate recipients with a unique opportunity to devote his or her full energies to research without the encumbrance of formal course work or teaching and administrative responsibilities.

While for many scientists, the postdoctoral fellowship is an important first step in launching a promising career, the postdoctoral fellowship can also serve as a “holding tank” until more adequate employment is secured (NRC 1981:60–61).

Since the late 1960s an increasing percent of doctoral scientists and engineers have begun their careers with a postdoctoral fellowship. In the life sciences, the percent of new Ph.D.s who were planning postdoctoral training upon graduation increased from just over 20 percent in 1963 to over 50 percent in 1995 (NRC 1998:29). While the use of postdoctoral fellowships varies widely by fields, with their most frequent use in the life sciences, followed by the physical sciences, the postdoctoral fellowship is an increasingly important aspect of the career in nearly all fields. Sonnert (1995) provides a detailed study of gender difference among those receiving prestigious postdoctoral fellowships from NSF and NRC. Unfortunately, most other studies of the postdoctoral experience fail to consider gender differences. For example, while the recent NRC (1998) study of the early career in the life sciences (where postdoctoral fellowships are most common) carefully considers the postdoctoral fellowship, it does not provide any comparisons by gender.

Table 4–10 shows the percent of men and women in the first five years: after the Ph.D. who hold postdoctoral fellowships in each of our survey years 1973, 1979, 1989, and 1995. The table highlights several key characteristics of fellowships. First, their use varies widely by field, with substantially more postdoctoral fellowships in the life and physical sciences. Second, since 1973 there has been a steady increase in the percent of scientists and engineers who have fellowships in the period immediately after the Ph.D., perhaps reflecting the relatively weak job market of recent years. Third, in fields where the postdoctoral fellowship is traditional, namely the life and physical sciences, women used to be about 5 percentage points more likely to have a fellowship early in the career. That trend has been reversed.

Unfortunately, our data are too limited to pursue more detailed analyses of gender differences in postdoctoral fellowships. To examine the postdoctoral experience, the focus must be on scientists in the period immediately following the Ph.D. By its design, the SED samples scientists and engineers at all stages of the career. Consequently, there are too few

Suggested Citation:"4: Labor Force Participation." National Research Council. 2001. From Scarcity to Visibility: Gender Differences in the Careers of Doctoral Scientists and Engineers. Washington, DC: The National Academies Press. doi: 10.17226/5363.
×

TABLE 4–10 Percent of Men and Women Within Five Years of the Ph.D. Who have Postdoctoral Fellowships, by Years of Survey and Field

 

Men

Women

1973

1979

1989

1995

1973

1979

1989

1995

Engineering

1.9

2.0

5.7

8.5

2.9

6.9

12.0

Mathematical Sciences

1.4

3.3

5.8

9.4

1.2

2.1

4.1

12.1

Physical Sciences

11.5

13.1

21.1

30.8

15.5

18.9

20.5

22.5

Life Sciences

11.2

23.8

32.7

37.1

18.0

28.8

28.0

37.0

Social/ Behavioral Sciences

1.7

3.2

3.5

5.4

2.9

4.7

4.2

7.0

 

Difference: Men—Women

 

1973

1979

1989

1995

Engineering

–0.9

–1.2

–3.6

 

Mathematical Sciences

0.2

1.2

1.7

–2.7

Physical Sciences

–4.0

–5.8

0.6

8.3

Life Sciences

–6.8

–5.0

4.7

0.1

Social/ Behavioral Sciences

–1.2

–1.5

–0.6

–1.6

NOTE:—indicates too few cases to analyze.

scientists, and especially women, within any given field to adequately explore gender differences in the fellowship experience.

Less than Full-Time Employment of Doctoral Scientists and Engineers

Female scientists are much more likely than men to be less than fully employed, as shown by Figure 4–5. The overall height of the bar shows the percent of scientists and engineers who are not working full time, with the divisions within each bar indicating the specific labor force status. Part-time employment is shown with dark gray; being unemployed by light gray; and not seeking work by the white region at the top. In 1973

Suggested Citation:"4: Labor Force Participation." National Research Council. 2001. From Scarcity to Visibility: Gender Differences in the Careers of Doctoral Scientists and Engineers. Washington, DC: The National Academies Press. doi: 10.17226/5363.
×

FIGURE 4–5 Employment status of those not working full time for combined fields, by sex, and year of survey.

women were 20 percentage points more likely to be less than fully employed. Since then gender differences have declined somewhat. In 1979 and 1989 there were small decreases for women, while rates were stable for men. In 1995 the rate increased 3 points for men and held steady for women. The net result is that gender differences in being less than fully employed have been reduced to 11 percentage points. Still, 17 percent of the female doctorates do not have full-time employment compared to only 6 percent of the male doctorates. There are also interesting changes in the relative proportion of scientists who are working part time, seeking work, and not seeking work. These issues are now considered.

Part-Time Employment

While women in all fields are much more likely than men to be working part time, Figure 4–6 shows that there are substantial differences across fields and changes over time in the percent of female doctorates who are working part time. Part-time employment for women decreased in all fields between 1973 and 1979, with decreases ranging from a low of 2 points in the life sciences to a high of 5 points in the physical sciences. Since 1979 rates of part-time employment have been highest in the social/ behavioral sciences where they have gradually increased. Rates are more similar among other fields, with increases in engineering and mathematics and decreases in the physical and life sciences. For men (figure not shown), rates are between 1 percent and 3 percent in all fields except the

Suggested Citation:"4: Labor Force Participation." National Research Council. 2001. From Scarcity to Visibility: Gender Differences in the Careers of Doctoral Scientists and Engineers. Washington, DC: The National Academies Press. doi: 10.17226/5363.
×

FIGURE 4–6 Percent of female Ph.D.s who are working part time, by field, and year of survey. NOTE: There are too few women in engineering in 1973 to estimate the percentage.

social/behavioral sciences, where between 3 percent and 4 percent are working part time. From 1989 to 1995, the rate of part-time employment for men increased by 1 to 2 points in all fields.

Seeking Work and Being Out of the Labor Force

Compared to the rate of unemployment in the United States population, unemployment is extremely rare for doctoral scientists and engineers. The lines in Figure 4–7 show the percent of the U.S. civilian population aged 20 and older who are seeking employment (BLS 1999) in each of our survey years. The dark gray bars show the corresponding percent of scientists and engineers who are unemployed. The percent of men in the United States population who are seeking work is about five times higher than for scientists and engineers whose rates are nearly constant at 1 percent. For female scientists and engineers, the situation is very different. Since 1973, there was a steady decrease in the percent of women who were seeking work, from 4 percent in 1973 to just over 1 percent in 1995. By 1995, the difference between male and female Ph.D.s in the percent seeking work was reduced to less than one-half point from a difference of three points in 1973. These low rates of unemployment in 1995 are consistent with what would be expected through the normal circulation of scientists and engineers among jobs.

There are much larger differences between male and female doctor-

Suggested Citation:"4: Labor Force Participation." National Research Council. 2001. From Scarcity to Visibility: Gender Differences in the Careers of Doctoral Scientists and Engineers. Washington, DC: The National Academies Press. doi: 10.17226/5363.
×

FIGURE 4–7 Rates of unemployment and being out of the labor force (i.e., not seeking work) for combined fields, by sex, and year of survey. NOTE: Rates for the U.S. population are the January rates for the civilian population ages 20 and older.

ates in the percent who are out of the labor force (i.e., not employed and not seeking work), represented by the light gray regions. These individuals are fully trained scientists and engineers who have not retired but who are no longer pursuing jobs in their field of training. While these scientists and engineers represent only a small percent of the total, they represent the loss of many years of training. Moreover, this loss occurs primarily to female scientists and engineers. For women, the rate hovers around 4 percent with some variations across fields (considered below). From 1973 to 1989, only three-tenths of 1 percent of the men were no longer seeking employment, a number that grew to 1 percent in 1995. The reasons for the change are unclear, but may correspond to aging of the male S&E labor force with an increasing proportion having accumulated sufficient financial resources to stop working.

Figure 4–8 shows field differences in the percent of female scientists and engineers who are unemployed. There is an overall downward trend in all fields except engineering where there is a spike to 4 percent in 1995. Note, however, that the figures in engineering are based on a small number of women. The largest drop occurred between 1973 and 1979, with smaller changes thereafter. The highest rates are in the physical and life sciences. Since the rates of seeking work for women in these fields do not correspond to higher rates for men, it is unlikely that the female rates reflect labor market conditions in these fields.

Suggested Citation:"4: Labor Force Participation." National Research Council. 2001. From Scarcity to Visibility: Gender Differences in the Careers of Doctoral Scientists and Engineers. Washington, DC: The National Academies Press. doi: 10.17226/5363.
×

FIGURE 4–8 Percent of women who are unemployed, by field, and year of survey.

FIGURE 4–9 Percent of women who are not employed and not seeking work, by field and year of survey.

Figure 4–9 shows the percent of women who are out of the labor force. That is, they are not employed and not seeking work. The rates for women are substantially higher than for men, with percentages reaching as high as 8 percent in the physical sciences in 1973. While there is a slight decrease between 1973 and 1989, this trend is reversed in 1995. There are also substantial differences across fields, with the highest rates in the physical sciences, followed by the life sciences, mathematics, and then the

Suggested Citation:"4: Labor Force Participation." National Research Council. 2001. From Scarcity to Visibility: Gender Differences in the Careers of Doctoral Scientists and Engineers. Washington, DC: The National Academies Press. doi: 10.17226/5363.
×

social/behavioral sciences. Given our findings in later analyses that lack of full-time employment for women is associated with being married and having a family, it is possible that higher rates occur in fields where it is more difficult for women to balance the responsibilities of work and home. Indeed, the higher rates occur in lab sciences where “being tied to the bench” may make it more difficult for a woman to nurture both a research program and a family. These fields are also among the fastest moving, where even a short absence can cause a scientist to quickly cease to be current with the latest research.

Trends over the Career

There are two approaches that can be used to examine how labor force participation changes as scientists and engineers age. First, a cohort of Ph.D.s can be followed as they progress through their career. This was done in Figure 4–4 when we looked at scientists with Ph.D.s from the 1970s using data from the 1979, 1989, and 1995 SDR. While this approach is ideal in many respects, it is limited since we have data only for three years. An alternative approach is to construct a synthetic cohort (see Chapter 2 for further details). For example, using data collected in 1995, scientists who obtained their degrees in 1994 are in the first year of the career; scientists with 1993 degrees are in the second year of the career; and so on. These age-defined cohorts can be thought of as a single group of scientists that are aging through the career. But, since each career year is based on a different cohort of scientists with degrees from different years, changes that are observed reflect both the effects of aging and the effects of the historical period (e.g., labor market conditions). Even with these limitations, synthetic cohorts provide valuable information on gender difference in labor force participation.

Figure 4–10 shows the major changes in the labor market behavior of Ph.D. scientists and engineers from 1973 to 1995 and key differences in the career paths of men and women. Consider first the distribution among labor force statuses for men and women in 1973, as shown in Panels A and B.4 The most striking difference is the much smaller percentage of women who are working full time in S&E at all stages of the career (shown by the smaller dark gray region at the bottom) and the much larger proportion of women who are less than fully employed. For both men and women, there is a decline in full-time employment over the career (shown

4  

The more jagged curves for women are due to the smaller number women with Ph.D.s during this period.

Suggested Citation:"4: Labor Force Participation." National Research Council. 2001. From Scarcity to Visibility: Gender Differences in the Careers of Doctoral Scientists and Engineers. Washington, DC: The National Academies Press. doi: 10.17226/5363.
×

FIGURE 4–10 Distribution of labor force outcomes, by sex and year of survey. NOTE: Percentages at each year since the Ph.D. are based on those scien-

Suggested Citation:"4: Labor Force Participation." National Research Council. 2001. From Scarcity to Visibility: Gender Differences in the Careers of Doctoral Scientists and Engineers. Washington, DC: The National Academies Press. doi: 10.17226/5363.
×

tists with Ph.D.s in the corresponding year. For example, year 1 in 1995 is based on scientists with Ph.D.s in 1994. Values are moving averages across five-year periods. Note that the vertical axis begins at 60 percent in order to highlight variation in the categories other than full time work in science and engineering.

Suggested Citation:"4: Labor Force Participation." National Research Council. 2001. From Scarcity to Visibility: Gender Differences in the Careers of Doctoral Scientists and Engineers. Washington, DC: The National Academies Press. doi: 10.17226/5363.
×

by the bottom two regions). For men this is largely the consequence of movement into part-time employment as retirement is approached. For women the change in full-time employment in S&E is due to increases in employment outside of S&E. Our data cannot distinguish the degree to which this change was due to women from earlier Ph.D. cohorts being less successful in obtaining positions in S&E or if female scientists found their S&E employment increasingly unsatisfactory as they aged, perhaps as a result of a lack of opportunity for promotion.

While similar trends are seen in 1995, there are several notable changes since 1973. First, there is a substantial increase in the percent of women working full time in all years. Second, smaller proportions of women are working part time as shown by the narrower white region in the center. Finally, there is a decrease in the percent of women seeking work, particularly at the start of the career.

In assessing these findings, keep in mind that the results are based on synthetic cohorts that reflect both changes as scientists age and differences in the scientific and engineering climate at different historical times. Nonetheless, it is clear that between 1973 and 1995 there has been convergence in the career paths of male and female scientists and engineers. Still, women are far more likely to be less than fully employed, leading to a substantial loss of doctoral women from the active scientific and engineering labor force. We now consider explanations for these gender differences.

EXPLANATIONS FOR DIFFERENCES IN LABOR FORCE PARTICIPATION

To understand the loss of female scientists and engineers from full-time employment, we must explore reasons for the lesser full-time employment of women. In this section, we consider two sources of information. First, we look at responses by scientists and engineers to questions on why they are working part time. Unfortunately, data are not available on reasons for unemployment or being out of the labor force. Second, we estimate statistical models to determine the association between individual characteristics and labor force status. Both sources of information demonstrate the profound effects of familial obligations for the labor force participation of women. It is also the case, however, that the direction of causality in the relationship between factors such as family responsibilities and employment remains unclear. For example, unsatisfactory employment prospects might encourage women to have children and reduce their commitment to work.

Suggested Citation:"4: Labor Force Participation." National Research Council. 2001. From Scarcity to Visibility: Gender Differences in the Careers of Doctoral Scientists and Engineers. Washington, DC: The National Academies Press. doi: 10.17226/5363.
×

Reasons for Part-Time Employment5

While female scientists and engineers are less likely to be married (as discussed in Chapter 3), married female scientists and engineers are twice as likely to have a spouse who is working full time compared to married men (NSF 1996:68). This could have at least two effects on the likelihood of part-time employment for women. First, Marwell, Rosenfeld, and Spilerman (1979) find that geographic constraints imposed by a dual career limit the ability of women to make strategic job changes in the academic marketplace. Such constraints might also increase the necessity of part-time employment as women try to accommodate their spouse’s career. Second, women are more likely to have primary responsibility for raising children and part-time employment could be a relatively attractive means of raising a family while maintaining links to a professional career.

In 1989 and 1995, the SDR asked scientists and engineers why they were working part time. Respondents chose one or more of the following: there were no jobs available; I had no need to work; and family obligations made part-time work necessary. Figure 4–11 shows that in 1989 nearly half of the women who worked part time cited family obligations and that the percent has increased over time. For men this was the least likely explanation. There are smaller gender differences in other reasons for part-time employment. In 1989, 53 percent of the men who were employed part time reported that they had no need to work full time compared to 31 percent of the women. These percentages were nearly reversed in 1995, when 30 percent of the men and 42 percent of the women indicated no need. A larger percent of men than women said they could not find full-time employment, while the precent of women remained constant at 19 percent.

While the SDR did not ask respondents to indicate the type of family obligation that kept them from full employment, our data suggest that this primarily involves responsibilities in raising children. Figure 4–12 plots the percentages of men and women who cite family reasons for part-time employment against how many years it is since the Ph.D. was obtained. If we assume that the Ph.D. was received at age 30, the horizontal axis corresponds to biological ages from 30 to 56. Immediately after the Ph.D. women cite family obligations 50 percent of the time. This rate increases till it peaks in year 8 for the 1989 survey and year 11 for the 1995 survey. The later peak in 1995 is consistent with recent societal trends for women having children when older. The rates decrease steadily from this point on. For men, the percentages generally stay below 10 percent, with a slight increase occurring from years 5 to 15.

5  

See Appendix Tables B-8-B-11 for additional data.

Suggested Citation:"4: Labor Force Participation." National Research Council. 2001. From Scarcity to Visibility: Gender Differences in the Careers of Doctoral Scientists and Engineers. Washington, DC: The National Academies Press. doi: 10.17226/5363.
×

FIGURE 4–11 Reasons for part-time employment, by sex, and year of survey. NOTE: Respondents can choose more than one response.

FIGURE 4–12 Percent who cite family reasons for working part time, by sex and year of survey. NOTE: Values are moving averages across 5-year periods.

Suggested Citation:"4: Labor Force Participation." National Research Council. 2001. From Scarcity to Visibility: Gender Differences in the Careers of Doctoral Scientists and Engineers. Washington, DC: The National Academies Press. doi: 10.17226/5363.
×

Factors Associated with Labor Force Participation6

Unfortunately, the SDR only asked respondents the reasons for part-time employment. To consider factors affecting other types of less than full employment, we must use statistical models to determine the degree to which characteristics of an individual, such as marital status and Ph.D. origins, are associated with labor force status after controlling for variables such as broad field and Ph.D. cohort. The effects of these control variables are not discussed since they were considered earlier in the chapter.

Marriage and Family

Past research has often found only limited effects of marriage and family on the careers of women in science and engineering. However, most of this research studied only women who were fully participating in S&E. But, for example, to say that the success of women who are full professors at research universities is not affected by family obligations does not imply that marriage and family did not affect their chances of staying in the labor force and thus having a chance to become a full professor. Conversely, women who do not become faculty at research universities may have had their career choices limited by familial status. Indeed, our analyses show that there is a strong association between marriage, children, and whether a female doctorate is less than fully employed, while there are only small effects for men. These results are now considered.

Overall, marriage and family are the most important factors differentiating the labor force participation of male and female scientists and engineers. Figure 4–13 plots the percent of male and female scientists and engineers in 1995 who are predicted by our model to work full time either in or out of S&E according to familial status.7 Four familial statuses are considered: single without children (black bar), married without children (dark gray bar), married with child one or more between the ages of 7 and 18 living at home (light gray bar), and married with one child or more younger than 7 living at home (white bar). Other statuses, such as di-

6  

See Appendix Table B-12 for additional data. Analyses are based on multinomial logit analyses of the five categories: full-time employment in S&E, full-time employment outside of S&E, part-time employment, unemployed and seeking work, and unemployed and not seeking work. Technical details are given in Chapter 2.

7  

Predictions are for an individual who is average on all of the variables in the model. See Chapter 2 for details.

Suggested Citation:"4: Labor Force Participation." National Research Council. 2001. From Scarcity to Visibility: Gender Differences in the Careers of Doctoral Scientists and Engineers. Washington, DC: The National Academies Press. doi: 10.17226/5363.
×

FIGURE 4–13 Predicted percent with full-time employment in 1995, by sex and familial status.

voiced with children, had too few cases to evaluate. Among men, those who are single are least likely to be working full time, with small increases for married men and those with children. In contrast, single women are most likely to be working full time. While being married slightly increases a man’s chances of full-time work, being married without children decreases the predicted proportion of women working full time by 5 percentage points. Having older children at home decreases the proportion by 8 more points, while being married with young children decreases the proportion with full-time employment by 22 points. It is interesting to note that as a consequence of the opposite effects of marriage and children for men and women, an identical 94 percent of single men and single women are expected to be working full time. That is, differences between men and women in labor force participation are eliminated if we compare single men to single women.

Figure 4–14 shows that for women there were some changes in the effects of marriage and family over time.8 The percent of women with young children who are predicted to work full-time increased by nearly 10 points between 1979 and 1989, with only a tiny increase in 1995. The predicted percent working among those with older children at home increased by over 3 points between each survey. Figure 4–15, plots differ-

8  

Data on marriage and family are not available for 1973.

Suggested Citation:"4: Labor Force Participation." National Research Council. 2001. From Scarcity to Visibility: Gender Differences in the Careers of Doctoral Scientists and Engineers. Washington, DC: The National Academies Press. doi: 10.17226/5363.
×

FIGURE 4–14 Predicted percent of women with full employment, by year of survey.

FIGURE 4–15 Differences in predicted labor force status between single women and married women with young children, by year of survey.

Suggested Citation:"4: Labor Force Participation." National Research Council. 2001. From Scarcity to Visibility: Gender Differences in the Careers of Doctoral Scientists and Engineers. Washington, DC: The National Academies Press. doi: 10.17226/5363.
×

ences between single women and married women with small children in the predicted proportion in each category of labor force participation. The biggest difference is in the proportion working full time. In 1979 women with small children were over 30 points less likely to be working full time compared to single women. This difference dropped to 22 points by 1995. The next two categories, part time work and not seeking work, account for the lesser full time work of women with young children. Women with children are nearly 15 points more likely to be working part time, with a slight drop in 1995. The next most likely work status is not seeking work. In 1979 women with young children were nearly 15 points more likely to be in this category, a difference that was reduced to around 10 points by 1995. There is very little effect of having young children for not working and seeking work. Similar analyses for men (not shown) found only the small effects of marriage and family. Overall, family has a significant effect on labor force status, but the effect appears to be gradually declining.

Baccalaureate Origins

The effects of baccalaureate origins on labor force participation were examined by including the Carnegie type of the baccalaureate institution. For men, we found no effect, but for women there was a small, negative association between receiving the bachelor’s degree from an exclusively undergraduate institution (e.g., a small liberal arts college) and working full time. Women with degrees from baccalaureate-only institutions were 2 percentage points less likely to be working full time in S&E occupations and roughly 2 points more likely to be working part time, after controlling for other factors. These effects were slightly smaller in 1995. It is possible that this represents differences in critical socialization to the scientific career that would be obtained with an undergraduate degree from an institution with research activities at the graduate level. On the other hand, it may reflect someone with lower career aspirations. We also examined whether receiving an undergraduate degree from a women’s college or university affected labor force participation. While some past research has suggested that attending a women’s college greatly increased a woman’s chances of being highly successful (Tidball and Kistiakowsky 1976), we found no effect on labor force participation.

Elapsed Time from Baccalaureate to Ph.D.

Logit analyses show that the time elapsed between the baccalaureate and the Ph.D. affected the labor force participation of scientists and engineers. Our measure of elapsed time is the difference between the date of

Suggested Citation:"4: Labor Force Participation." National Research Council. 2001. From Scarcity to Visibility: Gender Differences in the Careers of Doctoral Scientists and Engineers. Washington, DC: The National Academies Press. doi: 10.17226/5363.
×

the undergraduate degree and the date of the doctorate, thus combining time enrolled in a graduate program and interruptions such as predoctoral employment or raising a family. Past research suggests that individuals with elapsed times of more than 10 years have interrupted their education (Tuckman, Coyle, and Bae 1990). Accordingly, elapsed time was entered into the analyses as a binary variable indicating whether it took more than 10 years to complete the doctorate—that is, indicating whether it is likely that the education was interrupted.

Using data from 1995, Figure 4–16 plots the changes in the proportion of scientists and engineers predicted to be in each labor force status if the education was interrupted. The effects are in the same direction for men and women, but are larger for women. Individuals with interruptions are 5 to 7 percentage points less likely to be working full time in S&E, which is offset by a greater likelihood of working outside of S&E or working part time. Since interruptions between the bachelor’s degree and the Ph.D. may involve work outside of S&E (e.g., a social worker who goes back for a Ph.D. in psychology), it is possible that these men and women returned to their original employment after the completion of the degree. It is also possible that those who take longer to complete the degree are either less

FIGURE 4–16 Changes in labor force status if elapsed time between the baccalaureate and Ph.D. was more than 10 years, by sex for 1995.

Suggested Citation:"4: Labor Force Participation." National Research Council. 2001. From Scarcity to Visibility: Gender Differences in the Careers of Doctoral Scientists and Engineers. Washington, DC: The National Academies Press. doi: 10.17226/5363.
×

committed to their careers or alternatively that they are equally committed but not viewed by employers as being as as committed as their peers who complete the degree more quickly.

YEARS OF WORK EXPERIENCE9

The net effects of workforce participation can be summarized by the number of years that a scientist or engineer has spent working since the receipt of the doctorate. The impact of the greater time out of the full-time labor force for women is shown in Figure 4–17 for 1979 and 1989. Comparable data for 1973 and 1995 are not available. The lines plot the difference between the mean years of professional experience for men and women by the number of years since the Ph.D. For example, a value of 1.5 means that an average woman worked 1.5 years less than an average man. In 1979, for every year since the degree the female scientist worked 0.12 years less than an average male scientist; in 1989 this loss was reduced to 0.09, with the largest improvements being noticed between the 9th and 15th years of the career. Overall, compared to male scientists, nearly 10 percent of the potential work experience of female scientists is being lost.

FIGURE 4–17 Difference between men and women in mean years of work experience by years since the receipt of the Ph.D., by year of survey. NOTE: Values are 3-year moving averages.

9  

See Appendix Tables B-13-B-14 for additional data.

Suggested Citation:"4: Labor Force Participation." National Research Council. 2001. From Scarcity to Visibility: Gender Differences in the Careers of Doctoral Scientists and Engineers. Washington, DC: The National Academies Press. doi: 10.17226/5363.
×

A possible explanation for gender differences in professional work experience is that women are taking more time out of the workforce to care for their families. This explanation is consistent with many studies that have shown that within society as a whole women are more likely to be the primary caregivers (e.g., Moen 1985) and consequently to be absent from the paid labor force while they are working as caregivers. While we do not have information on the reasons for interruptions in the career, we do know an individual’s familial status at the time of the survey. Panels A and B of Figure 4–18 plot the difference between the mean years of work experience for male and female scientists according to their familial status, with the horizontal axis indicating years since the Ph.D. was received. In 1979, there was no difference in average work experience between single men and single women. For those who were married without children at home, the differences were small with some increase later in the career. But, for those who have children at home, the differences were much larger with an average woman with young children losing three-tenths of a year of work compared to men with young children for each year since the doctorate. Panel B shows that there were some decreases in the effects between 1979 and 1989, possibly reflecting increasing trends for women with families to remain in the labor force. Still, for married women and especially for those with young children, there are substantial losses in years of experience.

SUMMARY AND CONCLUSIONS

From 1973 to 1995 there were significant advances in the entry of women into S&E, but their advances did not completely overcome gender inequalities. While the representation of women in the S&E labor force is increasing in all fields, a greater proportion of women than men are not working full time. One way to summarize these differences, as well as to demonstrate the improvements since 1973, is to compare the percent of women working full time to the percent of men. Figure 4–19 plots the ratio of female and male rates of full-time employment. For example, if both 80 percent of men and 80 percent of women were working full time, the ratio would be at .8/.8=1. Values less than 1.0 indicate that women are less likely to be working full time. The figure shows that there were large improvements between 1973 and 1979, followed by gradual improvement through 1995. As shown earlier in the chapter, the net effect of the lower labor force participation of women is that as late as 1989 nearly 10 percent of the potential work activity of female scientists and engineers was lost as a result of their less than full employment.

Among the variables we consider, by far the strongest factor that affects a female scientist’s labor force participation is familial status. While

Suggested Citation:"4: Labor Force Participation." National Research Council. 2001. From Scarcity to Visibility: Gender Differences in the Careers of Doctoral Scientists and Engineers. Washington, DC: The National Academies Press. doi: 10.17226/5363.
×

FIGURE 4–18 Difference between mean work experience of men and women, by familial status, years since the Ph.D., and year of survey. NOTE: The vertical axis is the difference in the mean years for women and the mean years of experience for men.

Suggested Citation:"4: Labor Force Participation." National Research Council. 2001. From Scarcity to Visibility: Gender Differences in the Careers of Doctoral Scientists and Engineers. Washington, DC: The National Academies Press. doi: 10.17226/5363.
×

FIGURE 4–19 Ratio of the percent of women who are working full time in S&E to the percent of men who are working full time, by field and year of survey. NOTE: There are too few women in engineering in 1973 to compute statistic.

single women have rates of working full time that are identical to those of single men, being married and having children substantially reduces labor force participation for women but not for men. As summarized in Figure 4–20, married women are less likely to be working full time, women with older children are even less likely, and women with young children at home have rates of only around 70 percent.

Implications for Later Chapters

It is essential to understand the implications of our findings on labor force participation for the analyses of career outcomes in Chapters 5, 6, and 7. Those chapters examine the type of employer and work activity of scientists and engineers who are fully employed. Thus, even if the results in later chapters found no gender differences in career outcomes (which they do not find), there would still be important differences between male and female scientists and engineers in their success in moving into full-time employment. The less frequent full-time employment of women that is documented in the current chapter represents a significant loss of highly trained and talented scientific personnel, a loss that is not reflected in later chapters.

Suggested Citation:"4: Labor Force Participation." National Research Council. 2001. From Scarcity to Visibility: Gender Differences in the Careers of Doctoral Scientists and Engineers. Washington, DC: The National Academies Press. doi: 10.17226/5363.
×

FIGURE 4–20 Predicted percent of women with full-time employment, by marital status and year of survey.

Suggested Citation:"4: Labor Force Participation." National Research Council. 2001. From Scarcity to Visibility: Gender Differences in the Careers of Doctoral Scientists and Engineers. Washington, DC: The National Academies Press. doi: 10.17226/5363.
×
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×
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Suggested Citation:"4: Labor Force Participation." National Research Council. 2001. From Scarcity to Visibility: Gender Differences in the Careers of Doctoral Scientists and Engineers. Washington, DC: The National Academies Press. doi: 10.17226/5363.
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Suggested Citation:"4: Labor Force Participation." National Research Council. 2001. From Scarcity to Visibility: Gender Differences in the Careers of Doctoral Scientists and Engineers. Washington, DC: The National Academies Press. doi: 10.17226/5363.
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Suggested Citation:"4: Labor Force Participation." National Research Council. 2001. From Scarcity to Visibility: Gender Differences in the Careers of Doctoral Scientists and Engineers. Washington, DC: The National Academies Press. doi: 10.17226/5363.
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Suggested Citation:"4: Labor Force Participation." National Research Council. 2001. From Scarcity to Visibility: Gender Differences in the Careers of Doctoral Scientists and Engineers. Washington, DC: The National Academies Press. doi: 10.17226/5363.
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Suggested Citation:"4: Labor Force Participation." National Research Council. 2001. From Scarcity to Visibility: Gender Differences in the Careers of Doctoral Scientists and Engineers. Washington, DC: The National Academies Press. doi: 10.17226/5363.
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Although women have made important inroads in science and engineering since the early 1970s, their progress in these fields has stalled over the past several years. This study looks at women in science and engineering careers in the 1970s and 1980s, documenting differences in career outcomes between men and women and between women of different races and ethnic backgrounds.

The panel presents what is known about the following questions and explores their policy implications: In what sectors are female Ph.D.s employed? What salary disparities exist between men and women in these fields? How is marital status associated with career attainment? Does it help a career to have a postdoctoral appointment? How well are female scientists and engineers represented in management?

Within the broader context of education and the labor market, the book provides detailed comparisons between men and women Ph.D.s in a number of measures: financial support for education, academic rank achieved, salary, and others. The study covers engineering; the mathematical, physical, life, and social and behavioral sciences; medical school faculty; and recipients of National Institutes of Health grants.

Findings and recommendations in this volume will be of interest to practitioners, faculty, and students in science and engineering as well as education administrators, employers, and researchers in these fields.

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