Useful Stats: Trends in graduate students and postdocs by field of study

Graduate student enrollment and postdoctoral appointments have shifted in fields of study over the past decades, with many fields exploding in graduate enrollment and postdoctoral appointments. Computer and information sciences graduate students jumped from just 4% of all science enrollments in 1975 to nearly a quarter of the total by 2021, while engineering postdocs in biological, biomedical, and biosystems engineering jumped 5,671%– increasing from 3% in 1975 to 19% of all engineering postdocs by 2021. This edition of Useful Stats uses the full range of NSF GSS data to explore trends in graduate students (1975-2021) and postdoctoral appointees (1979-2021; postdocs) in science and engineering.

Methodological nuances and year-by-year changes can be found on the GSS survey page.

Trends in graduate student enrollment by field of study

Graduate student enrollment in science, engineering, and health has steadily increased since the 1980s, led by increases in science field enrollment (+275,000, or +117%, from 1975-2021). Engineering enrollment followed, increasing by approximately 100,000 (+146%), while health saw the smallest increase (57,000) but the largest relative increase (+222%).

A previous SSTI edition of Useful Stats goes into more detail on these broad enrollment numbers, exploring trends in each and their ups and downs over the years, while this article focuses solely on the sub-fields within science and engineering.

The material studied within these three broad fields has greatly changed over the past 40+ years, matching both advances in science and engineering and the needs of our ever-changing society.

In 1975, the majority of science graduate students were enrolled in the social sciences (approximately 78,000), followed by biological and biomedical sciences (46,000), psychology (36,000), and physical sciences (26,000). All four of these fields’ enrollment were more significant than the largest engineering field by enrollment: electrical, electronics, communications, and computer engineering (16,000).

The next largest engineering field by enrollment in 1975 was civil, environment, transportation, and related engineering fields (13,000) and industrial, manufacturing systems engineering and operations research (12,000).

By 2021, these top fields by enrollment have almost completely changed: computer and information sciences replaced the social sciences as the field with the most graduate students at 122,000 (a change from just 4% to 24% of all science graduate students), followed by biological and biomedical sciences (101,000), social sciences (82,000), and psychology (73,000). Similar to the 1970s, the top four fields by enrollment were all in the sciences.

The top engineering field stayed the same but saw an increase of 181% to over 45,000 students. Mechanical engineering (27,000) and other engineering (20,000) followed.

See Figure 1 below for a visual representation of the changes in science and engineering fields from 1975-2021.

Figure 1: Graduate enrollment in science and engineering from 1975-2021.

Trends in postdoctoral appointments by field of study

Postdoctoral data made available by the GSS goes back to 1979, slightly less than graduate student enrollment data, but shows a larger growth. The number of postdocs in science, engineering, and health has greatly increased since the 1970s, led by the number of those in science fields (+approximately 25,000, or 195%, from 1979-2021). The number of postdocs in health fields followed, with an increase of over 13,000 (+294%), while engineering postdocs, despite the largest relative growth (+682%), contributed the least (+7,000) to the overall increase.

More high-level trends for all three fields are available within SSTI’s prior coverage of GSS data, while this article focuses on only the sub-fields within science and engineering.

Postdoc trends in science and engineering follow a much different trend than those of graduate students. Between 1979 and 2021, the top fields for science (biological and biomedical sciences and  physical sciences) stayed the same but decreased in overall share of postdoctoral appointments. These two fields made up more than 87% of postdocs in science (over 80% of postdocs in both science and engineering fields) in 1979, but in 2021 dropped to 73% of all science postdocs (60% of science and engineering postdocs) despite a 148% increase within the two fields of study over the same period.

Engineering fields saw a paradigm shift between 1979 and 2021, with the rise of biological, biomedical, and biosystems engineering (28 to 1616, +5,671%), electrical, electronics, communications, and computer engineering (142 to 1,275, +798%), and mechanical engineering (143 to 1,200, +739%) among others. On the other hand, fields like metallurgical, mining, materials and related engineering fields plummeted in their share of postdoctoral appointments from 20% to just 7% (from 214 to 562).

See Figure 2 below for more information on trends in postdoctoral appointments in science and engineering.

Figure 2: Postdoctoral appointments in science and engineering fields from 1979-2021.