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B
STATISTICS ON GRADUATE EDUCATION OF SCIENTISTS AND ENGINEERS Michael McGeary
Study Director, Committee on Science,
Engineering, and Public Policy
Contents | OVERVIEW
| 100
| | THE GRADUATE STUDENTS
| 100
| | Tables:
| | B-1
| Distribution of Science and Engineering Graduate Students, by Field, 1992
| 101
| | B-2
| Distribution of US and Non-US Students, by Broad Field, 1992
| 102
| | B-3
| Female Science and Engineering Graduate Students, by Broad Field, 1992
| 103
| | B-4
| Members of Underrepresented Minorities, by Broad Field, 1992
| 104
| | B-5
| Increase in Full-Time Graduate Enrollment, by Field and Citizenship, 1982-1992
| 105
| | B-6
| Trends in First-Year and Beyond-First-Year Full-Time Enrollments in Doctorate-Granting Institutions, 1982-1992
| 106
| | B-7
| Sources of Major Support for Full-Time Science and Engineering Graduate Students in All Institutions, by Field, 1992
| 107
| | B-8
| Sources of Major Support for Full-Time Science and Engineering Graduate Students, 1982 and 1992
| 108
| | B-9
| Federal Sources of Support for Full-Time Science and Engineering Graduate Students in All Institutions, by Field and Agency, 1992
| 109
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B STATISTICS ON GRADUATE EDUCATION OF SCIENTISTS AND ENGINEERS Michael McGeary Study Director, Committee on Science, Engineering, and Public Policy
Contents OVERVIEW
100
THE GRADUATE STUDENTS
100
Tables:
B-1
Distribution of Science and Engineering Graduate Students, by Field, 1992
101
B-2
Distribution of US and Non-US Students, by Broad Field, 1992
102
B-3
Female Science and Engineering Graduate Students, by Broad Field, 1992
103
B-4
Members of Underrepresented Minorities, by Broad Field, 1992
104
B-5
Increase in Full-Time Graduate Enrollment, by Field and Citizenship, 1982-1992
105
B-6
Trends in First-Year and Beyond-First-Year Full-Time Enrollments in Doctorate-Granting Institutions, 1982-1992
106
B-7
Sources of Major Support for Full-Time Science and Engineering Graduate Students in All Institutions, by Field, 1992
107
B-8
Sources of Major Support for Full-Time Science and Engineering Graduate Students, 1982 and 1992
108
B-9
Federal Sources of Support for Full-Time Science and Engineering Graduate Students in All Institutions, by Field and Agency, 1992
109
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B-10
Mechanisms of Major Support for Full-Time Science and Engineering Graduate Students in Doctorate-Granting Institutions, 1991
110
B-11
Science and Engineering Graduate Students in Master's Degree Institutions and Doctorate Institutions, by Enrollment Status and Field, 1992
111
THE INSTITUTIONS
112
Tables:
B-12
Number of Academic Institutions with Science and Engineering Programs, by Highest Degree Level, 1991
112
B-13
Concentration of Science and Engineering Degree Awards by Type of Institution, 1991
113
B-14
Concentration of 80 Percent of Science and Engineering PhD Production in the 105 Research Universities, by Field, 1991
114
B-15
Number of Institutions by Highest Degree Level Since 1961, by Decade
114
SCIENCE AND ENGINEERING MASTER'S DEGREES
115
Tables:
B-16
Science and Engineering Master's Degrees, Awarded by Field, 1966-1991
115
B-17
Women as Percentage of Science and Engineering Master's Degree Recipients, by Field, 1991
116
B-18
Members of Underrepresented Minorities as Percentage of Science and Engineering Master's Degree Recipients, by Field, 1977-1991
117
B-19
Science and Engineering Master's Degrees Earned by Students Who Were Not US Citizens, by Field, 1977, 1985, and 1991
118
SCIENCE AND ENGINEERING DOCTORAL DEGREES
119
Tables:
B-20
Science and Engineering Doctorates Awarded, by Field, 1983-1993
119
B-21
Increases in Number of Science and Engineering Doctorates Awarded, by Field, 1988-1993
120
B-22
Women as a Percentage of Science and Engineering Doctorate Recipients, by Field, 1983-1993
121
B-23
Science and Engineering Doctorates Awarded to Women, by Field, 1983 and 1993
122
B-24
Members of Underrepresented Minorities as a Percentage of Science and Engineering Doctorate Recipients, by Field, 1983, 1988, and 1993
123
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B-25
Share of Science and Engineering Doctorates Earned by Students Who Were Not US Citizens, by Field, 1983 and 1993
124
B-26
Increase in Science and Engineering Doctorates Awarded to Non-US Citizens with Temporary Visas, by Field, 1983 and 1993
125
B-27
Science and Engineering Doctorates Awarded to Non-US Citizens with Temporary Visas, by Field, 1983 and 1993
126
B-28
Region and Country of Origin of Foreign Citizens with Temporary Visas Earning Science and Engineering PhDs, 1983 and 1993
127
B-29
Median Total Time-to-Degree for Doctorate Recipients, 1962-1993
128
B-30
Primary Sources of Support for Science and Engineering Doctorate Recipients, by Broad Field, 1993
131
POSTDOCTORATE EMPLOYMENT PLANS
131
Table:
B-31
Science and Engineering PhD Recipients with Definite Postgraduation Commitments in the United States, by Field and Type of Employer, 1970-1991
132
POSTDOCTORAL STUDY TRENDS
133
Tables:
B-32
Postdoctoral Study Plans of Recipients of Science and Engineering Doctorates from US Universities, 1985-1992
133
B-33
Postdoctoral Study Plans of Recipients of Science and Engineering Doctorates from US Universities, by Field, 1992
133
B-34
Science and Engineering Postdoctoral Appointees in Doctorate-Granting Institutions, by Field, 1982-1992
134
B-35
Trends in Net Growth of Science and Engineering Postdoctoral Appointee Positions in Doctorate-Granting Institutions, by Field, 1982 and 1992
135
B-36
Appointments of Postdoctoral Scientists and Engineers Who Were Not US Citizens in Doctorate-Granting Institutions, by Field, 1982 and 1992
136
B-37
Federally Supported Science and Engineering Postdoctoral Appointees in Doctorate-Granting Institutions, by Field, 1982 and 1992
137
B-38
Sources of Support for Science and Engineering Postdoctoral Appointees in Doctorate-Granting Institutions, by Field, 1992
138
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OVERVIEW About 1,500 institutions of higher learning in the United States have programs leading to degrees in science and engineering. Of those, nearly 300 offer doctoral-degree programs in science and engineering. They also offer master's degrees, and more than 400 nondoctoral academic institutions offer master's-degree programs in science and engineering. In 1992, about 430,000 graduate students were in science and engineering programs; 87% of them were at the 300 doctorate-granting institutions.
In 1992, about 80,000 master's degrees and 25,000 doctoral degrees were earned in science and engineering fields. About one-fourth of the doctorates were awarded in each broad field of science and engineering: physical/mathematical sciences, life sciences, social sciences, and engineering. The median time from the bachelor's degree to the PhD was 9.2 years. More than half of the master's degrees and 90% of the PhDs are awarded by the 150 universities that receive 90% of federal academic R&D funding.
About 5% of all science and engineering doctorate recipients in 1993 (14% of life-sciences PhDs) were supported by federal fellowships and traineeships. Another 61 % (including 78% of physical scientists and 69% of engineers) received external support, primarily research assistantships and teaching assistantships. Many of the research assistantships were funded by federal grants. About one-quarter of the science and engineering doctoral recipients (including one-half the social scientists) were self-supporting (including federally guaranteed loans).
More than one-third more doctorates in science and engineering were awarded in 1993 than in 1983. Seven-tenths of the net increase in doctorate awards went to foreign citizens with temporary visas, and most of the remaining increase was to US women. In 1993, nearly 30% of the doctorates were earned by women, up from about 25% in 1983. In 1992, 5.7% of PhDs were earned by members of underrepresented minorities in 1992, up from 4.1 % in 1983; most of the increase was earned by Hispanics. Foreign citizens with temporary visas greatly increased their share of US doctorates, earning 18.5% in 1983 and 32% in 1993; almost all the net increase was accounted for by citizens of Asian countries. Nearly half of the engineering PhDs went to foreign citizens with temporary visas.
THE GRADUATE STUDENTS In 1992, the National Science Foundation (NSF) estimated that about 431,600 students were enrolled in graduate science and engineering degree programs (NSF, 1994a:Table 1). Most (87%) were enrolled in doctorate-granting institutions, a proportion that has varied only slightly since the NSF survey began in 1975. Most (67%) were full-time students (this proportion was 72% in doctorate-granting institutions).
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It is not possible to tell which of these graduate students were enrolled in master's degree programs and which in doctoral programs, although many PhD recipients have master's degrees (72% in 1993) (NRC, 1995:Appendix Table A-3).
Table B-1, a comparison of the distribution of science and engineering graduate students among fields by type of institution and enrollment status shows that life-sciences graduate students were somewhat more likely than science and engineering graduate students overall to be at doctorate institutions and to be enrolled full-time. Social sciences and behavioral-science graduate students had the opposite pattern: they were somewhat more likely to be part-time and at master's institutions. Engineering graduate students were slightly more likely to be at doctorate institutions but more likely to be enrolled part-time.
TABLE B-1 Distribution of Science and Engineering Graduate Students, by Field, 1992
Field
All Institutions, All Students
Doctorate-Granting Institutions
All Students
Full-Time Students
TOTAL
431,613 (100%)
374,781 (100%)
270,984 (100%)
Physical/
mathematical sciences
106,548 (25.0%)
93,429 (25.2%)
69,053 (25.8%)
Astronomy
869
869
840
Physics
14,264
13,734
12,432
Chemistry
19,904
18,799
16,611
Physical sciences n.e.c.
459
209
128
Mathematical sciences
20,375
17,890
13,889
Environmental sciences
15,609
13,964
10,567
Computer sciences
36,396
29,042
15,554
Life sciences
66,046 (15.3%)
61,114 (16.3%)
51,676 (19.1%)
Agricultural sciences
11,609
10,891
8,907
Biological sciences
54,437
50,223
42,769
Social/behavioral sciences
139,644 (32.4%)
110,868 (29.6%)
77,464 (28.6%)
Social sciences
85,824
73,170
50,272
Psychology
53,820
37,698
27,192
Engineering
118,047 (27.3%)
108,292 (28.9%)
71,823 (26.5%)
SOURCE: Calculated from Table 1 in NSF, 1994a.
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Non-US Citizens Nearly 110,000 (25.3%) science and engineering graduate students were not US citizens in 1992. About 93,000 of them were enrolled full-time. Their distribution among fields differed from that of US-citizen science and engineering graduate students. Table B-2 shows the distribution of full-time science and engineering graduate students by citizenship and broad field in 1992. Those who were not US citizens were more likely to be studying engineering or the physical sciences and less likely to be in life-science or social/behavioral-sciences programs.
As a result, those who were not US citizens constituted relatively high proportions in some fields—46% of all full-time graduate students in engineering and 39% of those in the physical/mathematic sciences—but low proportions in other fields—27 % of all full-time graduate students in the life sciences and 17% of those in the social/behavioral sciences or psychology.
TABLE B-2 Distribution of US and Non-US Citizens, by Broad Field, 1992
Field
Full-Time Science and Engineering Graduate Student, All Institutions
US Citizen
Non-US Citizen
TOTAL
198,198 (100.0%)
92,795 (100.0%)
Physical/
mathematical sciences
45,177 (22.8%)
28,983 (31.2%)
Life sciences
39,146 (19.7%)
14,652 (15.8%)
Social/behavioral sciences
73,661 (37.2%)
14,908 (16.1%)
Engineering
40,214 (20.3%)
34,252 (36.9%)
SOURCE: Calculated from Tables 13 and 14 in NSF, 1994a.
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Female Graduate Students In 1992, more than 150,000 (35%) science and engineering graduate students were women (up from 25% in 1977). As Table B-3 shows, they were more likely to be enrolled in the life sciences or the social/behavioral sciences and less likely to be in the physical sciences or engineering. In fact, half of all female science and engineering graduate students were in social sciences and psychology programs.
As a result, the majority (54%) of graduate students in the social/behavioral sciences were women, as were 44% of those in the life sciences. Only 15% of engineering graduate students and 27% of those in the natural (physical, environmental, mathematical, and computer) sciences were female.
TABLE B-3 Female Science and Engineering Graduate Students, by Broad Field, 1992
Field
Number
Percentage Distribution Across Fields
Percentage of All Graduate Students
TOTAL
150,411
100.0
34.8
Physical/
mathematical sciences
28,719
19.1
26.6
Life sciences
29,223
19.4
44.2
Social/behavioral sciences
75,311
50.1
53.9
Engineering
17,158
11.4
14.5
SOURCE: Calculated from Table 8 in NSF, 1994a.
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Members of Underrepresented Minorities Fewer than 29,000 (9%) of science and engineering graduate students who were US citizens were members of underrepresented minorities—black, Hispanic, or American Indian. Compared with all US-citizen graduate students, they were much more likely to be studying social/behavioral sciences (53 versus 37%) and substantially less likely to be in the life sciences (13% versus 20%). Members of underrepresented minorities constituted 13% of US citizens in the social/behavioral sciences and about 7% of those in the other broad fields (see Table B-4).
TABLE B-4 Members of Underrepresented Minorities, by Broad Field, 1992
Field
Number
Percentage Distribution Across Fields
Percentage of All US-Citizen Graduate Students
TOTAL
28,866
100.0%
9.0
Physical/math sciences
4,917
17.0%
6.7
Life sciences
3,615
12.5%
7.2
Social/behavioral sciences
15,335
53.1%
12.6
Engineering
4,999
17.3%
6.5
SOURCE: Calculated from Table 2 in NSF, 1994a.
Growth Trends in Full-Time Graduate Enrollment Since 1982 In 1992, there were nearly 291,000 full-time science and engineering graduate students, 30.6% more than in 1982. The growth by field is presented in the first column of Table B-5. Much of the net growth came from foreign citizens; as overall enrollment was increasing by almost 2% a year, foreign enrollment was growing by more than 5% a year (NSB, 1993:50). The second and third columns of Table B-5 compare the increases in full-time science and engineering graduate students who were foreign citizens with those who were US citizens in 1982-1992, by field.
Enrollment increases were also driven by the increased participation of women—3 % a year, compared with 1 % among men, during the 1980s. There were absolute decreases in the number of male graduate students in the life, environmental, and social sciences and psychology (NSB, 1993:53).
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TABLE B-5 Increases in Full-Time Graduate Enrollment, by Field and Citizenship, 1982-1992 (percentages)
Citizenship
Field
All
Non-US
US
TOTAL
+30.6
+68.1
+18.4
Physical/
mathematical sciences
+33.7
+90.6
+12.2
Physical sciences
+27.8
+83.9
+7.1
Mathematical sciences
+35.5
+47.8
+28.6
Environmental sciences
-2.5
+63.3
-13.6
Computer sciences
+92.1
+170.3
+50.4
Life sciences
+14.8
+97.6
-0.8
Agricultural sciences
-6.2
+17.3
-14.1
Biological sciences
+20.4
+136.3
+2.3
Social/behavioral sciences
+26.2
+32.4
+25.1
Social sciences
+22.1
+30.1
+19.8
Psychology
+33.2
+53.9
+32.3
Engineering
+48.2
+60.6
+39.6
SOURCES: Calculated from Tables 13 and 14 in NSF, 1994a for 1992; Table B-5 in NSF, 1993a for 1982.
Growth in First-Year and Beyond-First-Year Enrollments, 1982-1992 The NSF survey of graduate students and postdoctorates in science and engineering fields began to collect information on the number of first-year full-time enrollments in 1982. The data indicate that first-year enrollments increased at a lower rate than total full-time enrollments until about 1989, after which they increased more rapidly for several years. During 1982-1992, first-year enrollments increased by 17% and beyond-first-year enrollments by 37% (Table B-6). It is difficult to interpret those data. Are the recent large increases in first-year enrollments the result of reports in the middle to late 1980s of impending shortfalls in the number of PhDs or the tendency of more college graduates to go to graduate school when economic conditions are poor? Also, how much of the higher rate of growth among beyond-first-year graduate students until recently was simply the manifestation of the steadily increasing degree requirements among science and engineering PhDs, and how much was due to graduate students' deliberately delaying completion of their degrees as short-term responses to poor job-market prospects?
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TABLE B-6 Trends in First-Year and Beyond-First-Year Full-Time Enrollments in Doctorate-Granting Institutions, 1982-1992
Year
First Year
Beyond First Year
1982
70,351
152,419
1983
72,152 (2.6%)
157,786 (3.5%)
1984
70,604 (-1.8%)
160,986 (2.0%)
1985
71,395 (1.1%)
163,100 (1.3%)
1986
73,167 (2.5%)
169,941 (4.2%)
1987
71,255 (-2.6%)
176,265 (3.7%)
1988
70,930 (-0.5%)
180,036 (2.1%)
1989
74,478 (5.0%)
182,677 (1.5%)
1990
76,405 (2.6%)
189,355 (3.7%)
1991
81,140 (6.2%)
196,211 (3.6%)
1992
82,481 (1.7%)
208,512 (6.3%)
SOURCES: Calculated from Tables B-34 and B-35 in NSF, 1992a for 1982; Tables B-24 and B-25 in NSF, 1993a for 1983-1994; unpublished NSF Tables for 1985-1992.
Sources and Mechanisms of Financial Support In 1992, science and engineering graduate students were supported in a number of ways by a variety of sources. For each full-time student, the NSF survey asks for the ''major" (i.e., largest) source of support (e.g., federal, institutional, and self) and the type (e.g., fellowship, and/or research assistantship). Table B-7 shows that the sources of support vary considerably from field to field. Although on the average 20% of full-time science and engineering graduate students received their major support from a federal source, this was the largest source of support for 32% of graduate students in biology and nearly 36% of graduate students in the physical sciences. Only 7% of graduate students in the social or behavioral sciences and 10% of those in the mathematical sciences were supported primarily by federal funds. Nearly twothirds of mathematical scientists and half of those in the physical sciences received their major support from their institutions (mostly in the form of research and teaching assistantships), but institutional funds were also an important source of graduate support in the other disciplines—between 32 and 45%. "Own funds" (including, however, federally guaranteed loans) were the major source of support for large fractions of graduate students in some fields—46% of those in computer science and 40% of those in the social and behavioral sciences—but for relatively few in physics, astronomy, and chemistry (6%) or the biological sciences (13%). Only a few percent received foreign support (although those completing the
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survey might not always have known whether those funding their own way—thus classified as self-supporting—were receiving foreign support). Finally, about 7% overall were receiving support from industry and domestic sources other than federal and institutional. About 11% of students in engineering and agricultural science were receiving such support.
TABLE B-7 Sources of Major Support for Full-Time Science and Engineering Graduate Students in All Institutions, by Field, 1992
Field
Total No.
Federal
Institu- tional
Other US
Foreign
Self
TOTAL
290,993
20.0%
41.3%
6.9%
2.1%
29.7%
Physical/
mathematical sciences
74,160
25.0%
47.0%
5.8%
1.6%
20.6%
Physical sciences
30,730
35.7%
50.0%
7.0%
1.1%
6.4%
Mathematical sciences
14,663
10.2%
65.1%
2.4%
2.0%
20.3%
Environmental sciences
11,150
30.9%
39.2%
7.1%
2.2%
20.6%
Computer sciences
17,617
15.0%
31.7%
5.9%
1.8%
45.6%
Life sciences
53,798
31.8%
43.4%
7.9%
2.3%
14.5%
Agricultural sciences
9,280
21.1%
38.7%
11.5%
6.2%
22.5%
Biological sciences
44,518
34.0%
44.4%
7.2%
1.5%
12.9%
Social/behavioral sciences
88,569
7.0%
42.0%
3.5%
1.7%
45.7%
Social sciences
54,183
6.3%
45.0%
3.7%
2.7%
42.3%
Psychology
34,386
8.1%
37.4%
3.2%
0.2%
51.1%
Engineering
74,466
22.1%
33.3%
11.4%
2.7%
30.5%
SOURCE: Calculated from Table 11 in NSF, 1994a.
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Those figures are for all PhDs in all fields, including humanities, education, and the professional (which have had the highest TTDs historically). The patterns vary widely by field, even within the sciences and engineering. Engineering and physical sciences have always had shorter than average completion times; social sciences, longer.
The increase in TTD has slowed considerably since about 1987, even though the recession of the early 1990s might have increased the incentive to stay in school a year or two longer.
TABLE B-29 Median Total Time-to-Degree for Doctorate Recipients, 1962-1993 (selected years)
Field
1962
1967
1972
1977
1982
1987
1992
1993
All fields (including humanities)
Registered
5.4
5.4
5.7
6.1
6.5
6.9
7.1
7.1
Total
8.8
8.1
8.2
8.7
9.6
10.4
10.5
10.5
All Science and Engineering
Registered
6.4
6.7
6.7
Total
8.6
9.1
9.2
Physical sciences
Registered
5.1
5.1
5.6
5.7
5.8
6.0
6.5
6.5
Total
6.5
6.0
6.5
6.9
6.9
7.4
8.1
8.3
Life sciences
Registered
5.3
5.4
5.5
5.7
6.0
6.5
6.7
6.8
Total
7.8
7.2
7.0
7.3
7.6
8.8
9.4
9.4
Social sciences
Registered
5.4
5.2
5.6
5.9
6.7
7.2
7.5
7.4
Total
9.0
7.7
7.5
8.0
9.2
10.4
10.6
10.4
Engineering
Registered
5.0
5.2
5.5
5.6
5.7
5.8
6.2
6.3
Total
7.1
7.2
7.5
7.5
8.0
8.1
8.7
8.8
SOURCE: Calculated from Table 6 in NRC, 1995.
In conducting the research for their recent book In Pursuit of the PhD, Bowen and Rudenstine (1992:113-119), noticed that TTD figures were lower for their sample of 10 schools. They consulted demographers who suggested a different method for determining TTD that should be more accurate. The method used by the Office of Scientific and Engineering
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Personnel (OSEP) and others determines the median number of TTD years for all those receiving their doctorates in a particular year. The demographers pointed out that this permits a bias if the cohorts entering graduate school are increasing or decreasing in size over time. Each entering class of PhD candidates has some fast finishers and some slow finishers. In a period such as the late 1950s and 1960s, when the number entering PhD programs was growing every year, the proportion of fast finishers showing up for their degrees a few years later increased and made the decreases in TTD larger than they would have been if cohorts had been steady. Similarly, when cohort sizes decrease, as they did in 1974-1984, the proportion of fast finishers getting their degrees a few years later goes down, increasing the apparent TTD. More recently, enrollments have gone up again, and that accounts for at least part of the decrease in TTD medians in the past several years.
Bowen and Rudenstine corrected for that bias by calculating average TTD of entering cohort, rather than graduating cohort. They asked, how long on the average, did it take those entering a PhD program (or getting their bachelor's degrees in year X to get their doctorates? They found that use of the entering-cohort method gave an increase in TTD of about 10% over the preceding 15-20 years, not 30%. They admitted that any lengthening in the already-long TTD is a serious problem but said that its magnitude and newness had been exaggerated.
A study of TTD by staff of OSEP reviewed the literature on the causes of increasing TTD (Tuckman, et al., 1990). They found that earlier studies had looked at sociological, demographic, economic, and institutional factors, although few had looked at them all and undertaken a causal analysis. They developed a model of TTD with five vectors of variables: family background characteristics, individual abilities and interests, tuition and financial aid, institutional environment and policies, and economic and social forces. They tested the model in 11 fields using data from the Survey of Earned Doctorates and found a variety of factors that affected registered time-to-degree (RTTD) or total time-to-degree (TTTD), including the availability and form of student support, labor-market conditions, sociodemographic characteristics of the doctorate recipients, and characteristics of the undergraduate and graduate institutions. Yet no factor or set of factors consistently explained the general upward trend in TTD. That might be because TTD is poorly measured (the study was based on the graduating, rather than the entering, cohort), or because the data are inadequate. They are aggregate data, and some measure the variables of interest only indirectly; other variables, such as increasing complexity of subject matter or the incentive for faculty to keep students longer as cheap labor on research projects, are not measured at all.
As for negative consequences, the following have been mentioned (Tuckman, et al., 1990):
· The increasing time spent in graduate school increases the time it takes for the supply of PhDs to respond to shifts in market demand, and that has both social and individual costs (if demand goes up, there are not enough qualified people; if it falls, highly capable people cannot be employed in their field of training).
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· Increasing TTD will discourage some highly qualified candidates from staying in science (perhaps some of the most qualified students, who can more easily find attractive alternatives).
· Delayed start of career reduces the total years of productivity for society and the return on investment for the individual.
Bowen and Rudenstine (1992) also studied the effects of financial support in some detail in their 10-school sample. They found that it mattered. Students who received financial aid had much higher completion rates and shorter TTD than students who relied on their own resources. In the sciences, the form of the aid had an effect on completion and TTD; research assistantships had the best effect, fellowships a close second, and teaching assistantships the worst effect. They also found that the NSF fellowship program had been very successful in reducing median TTD (4.9 years versus 5.6 years for those who were not NSF fellows in an eight-university group). Interpreting such findings is problematic, however. Did the NSF fellows finish earlier because of the fellowship form of support itself or because they were selected through a rigorous process that selected more-motivated students?
In conclusion, both RTTD and TTTD have been increasing for a long time, with the exception of the 1960s. Presumably, the increases are caused in part by the increasing complexity of knowledge and techniques to be mastered in doctorate programs and in part by less-desirable or less-excusable reasons (e.g., an increase in tuition costs and a decrease in federal aid, which force students to work more during graduate school, or a desire of faculty to keep students working on research projects). They are also caused in part by the increasing participation of women and minority-group members, who generally have longer TTDs.
According to Bowen and Rudenstine, having outside aid does improve completion and TTD rates. The form of the aid—fellowships, research assistantships, or teaching assistantships—might have little independent effect.
Source of Support The Survey of Earned Doctorates (SED) administered yearly by OSEP for NSF asks new PhDs to list their primary source of support during graduate school. The data for 1993 are displayed in Table B-30. It should be noted, however, that the nonresponse rate to this question was 34%, for unknown reasons (it was 23% in 1991, and 30% in 1992). It also should be noted that federally funded research assistantships are listed with other research assistantships under ''university" because students often do not know the source of support for their research assistantships. Federal loans are listed under "personal." "Other" includes national fellowships, employer funds, and support from foreign governments, state governments, and other nonspecified sources. The "life sciences" include "health science" PhDs as well as the biological and agricultural scientists listed in the other tables in this appendix.
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A brief analysis of the table shows that a relatively large percentage of the PhD recipients in social sciences are self-supporting—nearly half, compared with 10-15% of those in the physical sciences and engineering and a fifth of those in the life sciences.
PhDs in the life sciences receive the most direct federal support, probably resulting from the large fellowship and traineeship programs of the National Institutes of Health.
Most PhDs in the physical sciences and engineering, and to a lesser extent the life sciences, receive their primary support from their universities. That includes federally funded research assistantships, as well as other research and teaching assistantships.
TABLE B-30 Primary Sources of Support for Science and Engineering Doctorate Recipients, by Broad Field, 1993 (percentages)
Field
Personal
University
Federal
Other
TOTAL
23.8
61.4
7.5
7.3
Physical sciences
12.1
77.9
4.5
5.4
Life sciences
21.4
56.8
14.4
7.4
Social sciences
47.8
41.6
5.0
5.6
Engineering
14.7
69.3
4.9
11.1
SOURCE: Calculated from Table 11 in NRC, 1995.
POSTDOCTORATE EMPLOYMENT PLANS According to the SED, among new science and engineering PhDs who had definite postgraduation plans, the percentage planning to work in academe (college or university) was 48% in the early 1960s (NRC, 1978:Table 30). That figure increased to 57.0% in 1970 before falling steadily to 44.1% in 1980 (NSF, 1993b:Table 15) and 40.4% in 1993 (NSF, 1994f:Table 7). Meanwhile, the proportion of new science and engineering PhDs going to business and industry grew from about 22% in the 1960s to 26.5% in 1970 and 36.2% in 1993.
Note that Table B-31 does not include those with definite plans for postdoctoral study in the United States, almost all at universities. These numbered 2,789 in 1970, 3,571 in 1980, 4,676 in 1990, and 5,739 in 1993 (NSF, 1993b:Table 15, 1994f:Table 7).
It also should be noted that the percentage of science and engineering PhDs who had definite plans at the time of the SED survey fell from 76.6% in 1970 to 72.0% in 1980, 64.0% in 1990, and 60.1% in 1993 (NSF, 1993b:Table 15, 1994f:Table 7).
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TABLE B-31 Science and Engineering PhD Recipients with Definite Postgraduation Commitments in the United States, by Field and Type of Employer, 1970-1991
1970
1975
1980
1985
1990
1991
Field
No.
Percentage
No.
Percentage
TOTAL
9,216
100.0
8,187
7,285
6,614
7,175
7,403
100.0
College/university
5,263
57.1
4,287
3,228
2,851
2,952
3,099
41.9
Elementary/
secondary school
44
0.5
99
113
95
81
111
1.5
Government
1,015
11.0
1,365
1,142
885
871
890
12.0
Nonprofit
organization
408
4.4
443
537
502
493
492
6.6
Industry/business
2,399
26.0
1,886
2,139
2,099
2,452
2,488
33.6
Self-employed
48
0.5
71
101
145
240
229
3.1
Other and unknown
39
0.4
36
25
37
86
94
1.3
SOURCE: Calculated from Table 5 in NSF, 1993b.
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POSTDOCTORAL STUDY TRENDS TABLE B-32 Postdoctoral Study Plans of Recipients of Science and Engineering Doctorates from US Universities, 1985-1992
PhD Recipients
1985
1987
1988
1989
1990
1991
1992
TOTAL
19,164
20,203
21,411
22,294
23,440
24,543
25,248
Postdoctoral plans
5,941
6,728
7,216
7,268
8,087
8,811
9,316
Fellowship
49.0%
48.0%
48.7%
49.7%
49.0%
49.9%
50.7%
Research associate
41.3%
42.9%
43.0%
40.5%
41.7%
41.5%
41.2%
Traineeship
4.5%
3.6%
3.9%
4.0%
4.1%
3.9%
3.3%
Other
5.2%
5.1%
4.4%
5.5%
4.9%
5.0%
5.1%
SOURCE: Calculated from Appendix Table A-3 in NRC, 1993.
TABLE B-33 Postdoctoral Study Plans of Recipients of Science and Engineering Doctorates from US Universities, by Field, 1992
PhD Recipients
Physical Sciences
Engineering
Life Sciences
Social Sciences
Total Science and Engineering
TOTAL
6,498
5,437
7,108
6,205
25,248
Postdoctoral plans
3,022
1,202
4,066
1,036
9,316
Fellowship
53.1%
34.4%
57.5%
64.7%
50.7%
Research associate
42.8%
58.8%
32.3%
19.2%
41.2%
Traineeship
2.2%
4.1%
2.6%
9.6%
3.3%
Other
1.9%
3.2%
7.7%
6.6%
5.1%
SOURCE: Calculated from Appendix Table A-3 in NRC, 1993.
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TABLE B-34 Science and Engineering Postdoctoral Appointees in Doctorate-Granting Institutions, by Field, 1982-1992
Field
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
All Science and Engineering
14,672
15,657
16,168
16,920
17,901
18,760
19,759
20,962
21,604
23,018
24,024
Science, Total
13,694
14,556
14,974
15,573
16,505
17,319
18,075
19,054
19,661
20,781
21,680
Physical sciences
4,281
4,444
4,386
4,517
4,843
4,953
5,187
5,355
5,507
5,623
5,772
Physics
1,326
1,350
1,320
1,342
1,527
1,548
1,578
1,678
1,715
1,763
1,954
Chemistry
2,805
2,973
2,906
2,995
3,151
3,246
3,429
3,462
3,580
3,627
3,573
Environmental Sciences
335
415
488
375
417
420
499
459
605
645
709
Mathematical Sciences
194
170
203
226
201
228
280
223
247
206
201
Computer Sciences
46
82
63
74
74
100
91
78
71
157
149
Agricultural Sciences
279
307
375
373
409
441
454
512
529
574
634
Biological sciences
7,756
8,355
8,707
9,164
9,722
10,346
10,752
11,518
11,799
12,648
13,287
Psychology
520
435
422
495
517
454
493
535
457
503
521
Social sciences
283
348
330
349
322
377
319
374
446
425
407
Engineering, Total
978
1,101
1,194
1,347
1,396
1,441
1,684
1,908
1,943
2,237
2,344
Chemical engineering
174
198
245
273
295
309
423
466
551
578
554
Materials
166
204
168
245
250
283
325
323
370
401
458
Mechanical
130
182
196
207
239
216
216
302
218
329
355
Electrical
176
174
171
176
172
175
186
193
241
300
307
SOURCE: Calculated from Table C-25 in NSF, 1992a; and, for 1991 and 1992, NSF, unpublished tables.
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TABLE B-35 Trends in Net Growth of Science and Engineering Postdoctoral Appointee Positions in Doctorate-Granting Institutions, by Field, 1982 and 1992
Growth, 1982-1992
Percentage Distribution of Postdoctoral Positions Among All Fields
Field
1982
1992
Difference
Percentage
1982
1992
All Science and Engineering
14,672
24,024
9,352
63.7
100.0
100.0
Science, Total
13,694
21,680
7,986
58.3
93.3
90.2
Physical sciences
4,281
5,772
1,491
34.8
29.2
24.0
Physics
1,326
1,954
628
47.4
9.0
8.1
Chemistry
2,805
3,573
768
27.4
19.1
14.9
Environmental Sciences
335
709
374
111.6
2.3
3.0
Mathematical Sciences
194
201
7
3.6
1.3
0.8
Computer Sciences
46
149
103
223.9
0.3
0.6
Agricultural Sciences
279
634
355
127.2
1.9
2.6
Biological sciences
7,756
13,287
5,531
71.3
52.9
55.3
Psychology
520
521
1
0.2
3.5
2.2
Social sciences
283
407
124
43.8
1.9
1.7
Engineering, Total
978
2,344
1,366
139.7
6.7
9.8
Chemical engineering
174
554
380
218.4
1.2
2.3
Materials
166
458
292
175.9
1.1
1.9
Mechanical
130
355
225
173.1
0.9
1.5
Electrical
176
307
124
74.4
1.2
1.3
SOURCE: Calculated from Table C-25 in NSF, 1992a; and, for 1991 and 1992, NSF, unpublished tables.
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TABLE B-36 Appointments of Postdoctoral Scientists and Engineers Who Were Not US Citizens in Doctorate-Granting Institutions, by Field, 1982 and 1992
Growth, 1982-1992
Percentage of All Postdocs within Field
Percentage of All Non-US Science and Engineering Postdocs
Field
1982
1992
Difference
Percentage
1982
1992
1982
1992
All Science and Engineering
5,961
12,627
6,666
111.8
40.6
52.6
100.0
100.0
Science, Total
5,304
11,053
5,749
108.4
38.7
51.0
89.0
87.5
Physical sciences
2,367
3,506
1,139
48.1
55.3
60.7
39.7
27.8
Physics
673
1,099
426
63.3
50.8
56.2
11.3
8.7
Chemistry
1,661
2,311
650
39.1
59.2
64.7
27.9
18.3
Environmental Sciences
121
276
155
128.1
36.1
38.9
2.0
2.2
Mathematical Sciences
126
109
-17
-13.5
64.9
54.2
2.1
0.9
Computer Sciences
12
50
38
316.7
26.1
33.6
0.2
0.4
Agricultural Sciences
116
275
159
137.1
41.6
43.4
1.9
2.2
Biological sciences
2,397
6,574
4,177
174.3
30.9
49.5
40.2
52.1
Psychology
65
127
62
95.4
12.5
24.4
1.1
1.0
Social sciences
100
136
36
36.0
35.3
33.4
1.7
1.1
Engineering, Total
657
1,574
917
139.6
67.2
67.2
11.0
12.5
Chemical engineering
133
415
282
212.0
76.4
74.9
2.2
3.3
Materials
138
331
193
139.9
83.1
72.3
2.3
2.6
Mechanical
100
211
111
111.0
76.9
59.4
1.7
1.7
Electrical
94
186
92
97.9
53.4
60.6
1.6
1.5
NOTE: Includes permanent residents and those with temporary visas.
SOURCE: Calculated from Table C-30 in NSF, 1992a; and, for 1991 and 1992, NSF, unpublished tables.
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TABLE B-37 Federally Supported Science and Engineering Postdoctoral Appointees in Doctorate-Granting Institutions, by Field, 1982 and 1992
Field
Growth, 1982-1992
Percentage of All Postdocs within Field
Percentage of All Federally Supported Postdocs
1982
1992
Difference
Percent
1982
1992
1982
1992
All Science and Engineering
11,119
17,660
6,541
58.8
75.8
73.5
100.0
100.0
Science, Total
10,447
16,050
5,603
53.6
74.8
74.0
94.0
90.9
Physical sciences
3,600
4,589
989
27.5
64.1
79.5
32.4
26.0
Physics
1,156
1,641
485
42.0
87.2
84.0
10.4
9.3
Chemistry
2,307
2,730
423
18.3
82.2
76.4
20.7
15.5
Environmental Sciences
255
556
301
118.0
76.1
78.4
2.3
3.1
Mathematical Sciences
46
143
97
210.9
23.7
71.1
0.4
0.8
Computer Sciences
25
113
88
352.0
54.3
75.8
0.2
0.6
Agricultural Sciences
166
417
251
151.2
59.5
65.8
1.5
2.4
Biological sciences
5,825
9,695
3,870
66.4
75.1
73.0
52.4
54.9
Psychology
392
358
-34
-8.7
75.4
68.7
3.5
2.0
Social sciences
138
179
41
29.7
48.8
44.0
1.2
1.0
Engineering, Total
672
1,610
938
139.6
68.7
68.7
6.0
9.1
Chemical engineering
100
340
240
240.0
57.5
61.4
0.9
1.9
Materials
121
284
163
134.7
72.9
62.0
1.1
1.6
Mechanical
94
250
156
166.0
72.3
70.4
0.8
1.4
Electrical
118
229
111
94.1
67.0
74.6
1.1
1.3
NOTE: These are postdoctoral appointees for whom federal agencies and programs are "the source of the largest amount of their support" (those supported by federal loans are not included).
SOURCE: Calculated from Table C-27 in NSF, 1992a; and, for 1991 and 1992, NSF, unpublished tables.
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TABLE B-38 Sources of Support for Science and Engineering Postdoctoral Appointees in Doctorate-Granting Institutions, by Field, 1992
Federal Sources
Field
Total
Total
Fellowships (%)
Traineeships(%)
Research Grants(%)
Non Federal Sources
All Science and Engineering
24,024
17,660
11.1
7.6
81.3
6,364
Science, Total
21,680
16,050
11.8
8.2
80.0
5,630
Physical sciences
5,772
4,589
7.5
0.8
91.7
1,183
Physics
1,954
1,641
4.4
0.2
95.4
313
Chemistry
3,573
2,730
8.5
1.2
90.3
843
Environmental Sciences
709
556
7.9
1.1
91.0
153
Mathematical Sciences
201
143
16.1
4.2
79.7
58
Computer Sciences
149
113
1.8
0.9
97.3
36
Agricultural Sciences
634
417
9.8
0.5
89.7
217
Biological sciences
13,287
9,695
13.9
11.9
74.2
3,592
Psychology
521
358
14.2
23.5
62.3
163
Social Sciences
407
179
27.4
14.5
58.1
228
Engineering, Total
2,344
1,610
3.7
1.1
95.2
734
Chemical engineering
554
340
0.9
0.9
98.2
214
Materials
458
284
1.1
0.0
98.9
174
Mechanical
355
250
4.4
2.4
93.2
105
Electrical
307
229
3.5
0.0
96.5
78
SOURCE: Calculated from NSF unpublished data.
Representative terms from entire chapter:
engineering doctorates
