Recently I was invited by Rich Feller of Colorado State University to give a presentation at a meeting about STEM careers--that is, careers that involve science, technology, engineering, or mathematics. Many observers of the American workforce are worried about how our country will stay competitive if our college students continue to move away from these disciplines and instead pursue degrees in business and the humanities.
A research article I encountered this week pointed out some of the reasons why the PhD degree in STEM fields has lost some of its appeal. (Note, however, that many STEM careers do not require a doctoral degree.) John Bound, Sarah Turner, and Patrick Walsh, in "Internationalization of U.S. Doctorate Education”  (Population Studies Center Research Report 09-675, March 2009) note that, on average, recipients of a bachelor’s degree earn higher salaries by going into a line of work that does not entail getting a PhD in science. Although the earnings of doctoral-level scientists have increased over the last decade, bachelor’s-degree holders as a group (not just those in science) have seen even higher increases in earnings. (The exception is PhDs in the physical sciences, whose increase in earnings matches that of bachelor’s-holders in general.) The opposite was true in the late 1950s and early 1960s, when scientists with advanced degrees saw faster income growth than other college graduates.
Part of the reason for the earnings penalty of the science-PhD career path is the increasing importance of postdoctoral studies. Between the 1970s and the 1990s, the amount of time it took between entering graduate school and completing training increased from less than 10 years to 11.8 years. Young people who want to afford some of the comforts of adult life, such as starting a family, are understandably reluctant to commit to years of long work hours, low pay, and limited opportunities for a spouse’s employment.
Another finding reported in the paper is that scientists’ earnings no longer experience the large swings that used to result from changes in federal support for research. Apparently the large number of foreign graduate students in the sciences has created a pool of workers who are able to fill science jobs when funding is available here or to depart for their home countries when funding dries up here, thus dampening the former swings in America’s scientific labor market.