Changing Demographics of U.S. Science-Engineering PhDs

In 1966, U.S.-born white males received 71 percent of science and engineering PhDs... By the year 2000, (it was) just 35 percent.

In 1966, U.S.-born white males received 71 percent of science and engineering PhDs, U.S.-born females earned 6 percent of those degrees, and foreign-born students received 23 percent of those doctorates. By the year 2000, U.S.-born white males received just 35 percent of science and engineering PhDs, while 25 percent of those doctorates were awarded to females and 39 percent to foreign-born students. In Where Do New U.S.-Trained Science-Engineering PhDs Come From? (NBER Working Paper No.10554) authors Richard Freeman, Emily Jin, and Chia-Yu Shen also find that between 1970 and 2000 there was a huge increase in the number of science and engineering PhDs with undergraduate degrees from foreign institutions.

Among U.S. citizens, there has been a substantial upward trend in the proportion of PhDs granted to minorities: Asians and Pacific Islanders, blacks, and Hispanics. They earned fewer than 3 percent of all PhDs granted to Americans in 1966, and 9 percent of those degrees in 2000. In the case of science and engineering PhDs only, minorities increased their share of the PhDs received by U.S. citizens to 2.7 percent in 2000, compared to a negligible number in 1973. But their PhD share remains well below their share of the total population.

The authors note that "there is no clear explanation why women and minorities have chosen science and engineering PhDs in increasing numbers while fewer white men have gone on to earn science and engineering PhDs." One possibility is that they find these degrees financially more attractive. But this demographic group is also entering medical and law schools in greater number. So "it cannot be much of the story," the authors write.

One reason for the pickup in foreign students, particularly those with foreign bachelors' degrees, is that they often can earn much more from a U.S. doctorate than from working in other careers in their native country. That's in part because the science and engineering doctorate opens the door to working in the United States or working for U.S. and other multinational firms. American students, the authors write, have other diverse U.S. educational prospects, such as medical school, law school, and business school, and they can work as scientists or engineers without obtaining a PhD. So, they have less incentive to invest in a science and engineering PhD than comparable foreigners with undergraduate degrees.

In the United States, the number of universities and programs granting science and engineering PhDs has increased substantially. In 1970, 214 universities granted them; in 2000, the number had grown to 339 universities/campuses. In 1960, there were 6,520 science and engineering PhD graduates in science and engineering. By 1970 there were 18,052 PhD graduates and by 2000, there were 29,951. Among the big schools, producing 400-500 science and engineering graduates a year, are: the University of California, Berkeley; University of Illinois at Urban; University of Wisconsin at Madison; University of Michigan; University of Minnesota; MIT; and Stanford.

This study finds that the proportion of science and engineering PhDs coming out of such traditional leading doctorate institutions has declined. These universities have tended to maintain the size of their PhD programs, so that growth in the number of PhDs has occurred largely from smaller, less prestigious, yet often selective, schools. In the year 2000, women were less likely to obtain a PhD from the higher quality and larger universities than were other demographic groups. Perhaps, the authors suggest, women tended to enroll in smaller, newer PhD programs because they specialized in biological science areas. Or, the women didn't want to travel so far from home for family reasons. Or, they just didn't get admitted to the most prestigious and larger school programs.

Further, schools granting PhDs in science and engineering now face a "highly competitive" market, one which 30 years ago was only "moderately concentrated using standard definitions of market concentration from industrial organization," the authors find. The increase in science and engineering PhDs in the United States largely came from an expansion of smaller and less prestigious programs. One indication of this trend is that the proportion of PhDs coming from universities in the top ten among recipients of federal R and D money fell sharply from 1985 to 2000: indeed, the number of PhDs from the top ten R and D schools was lower in 2000 than in 1985.

An economic explanation for this trend, the authors note, is that the cost of expanding PhD programs at traditional PhD-producing universities can be quite high, because of capacity constraints set by faculty, plant, or other characteristics of existing programs. Another explanatory factor could be the willingness of state legislatures to fund a new PhD program in their own state universities, but not to support the education of students from their state at a program in some rival state. Private institutions may find it easier to raise funds to improve the quality of existing programs than to develop a "clone institution" at some other location.

This study uses data from the annual Survey of Earned Doctorates to detect demographic changes in science and engineering PhDs. The number of these graduates is relatively small when compared to, say, bachelors' degrees. But these PhD graduates often are considered significant to a nation's technological competitiveness.

-- David R. Francis