Where will chemical professionals come from in the future? Nobody can be certain. But detailed analysis of long-term trends in the number of Ph.D. graduates each year in chemistry and chemistry-related disciplines provides some indications of what to expect for the demographics and the nature of the chemical enterprise.
For traditional classic chemistry--organic, inorganic, and the like--the prognosis for the significant growth needed to reach new high ground in the number of graduates is not good. According to the latest annual National Science Foundation compilation of data on new Ph.D. graduates in all disciplines, the number of chemistry graduates was down for the fourth year in a row in 2002 and about 15% below both the all-time high of 2,257 set in 1994 and the previous high of 2,238 set in 1970.
The trends point to fewer men in absolute terms, a continuing increase in the percentage of graduates who are women, further slow gains for underrepresented minorities, a bottoming out of the long decline in the number of graduates who are U.S. citizens, and a continued need by chemistry departments for graduate students who are not U.S. citizens.
The most dramatic long-term change has been the plunge in the number of white male U.S. citizens earning chemistry Ph.D. degrees. In 1970, it was more than 1,500. For 2002, it was down to less than 700.
For the chemistry-related sciences such as biochemistry and materials science, the fundamentals appear stronger. The combined total of such graduates in 2002 was 13% lower than the high set in 1997. But it was still almost twice what it had been in 1970.
A quantitative look at what has happened over the past generation reveals that the 1,922 Ph.D. graduates in classic chemistry in 2002 were considerably fewer than the 2,238 in 1970. But the 2,739 graduates in chemistry-related fields in 2002 can be compared with 1,391 such graduates in 1970. For chemistry and chemistry-related fields combined, the totals are 3,629 for 1970 and 4,661 for 2002, with a peak of 5,307 in 1998.
This all means that chemistry's share of the chemistry/chemistry-related total fell steadily from 62% in 1970 to 41% in 2002.
These hard data can be viewed as tracing the erosion of classic chemistry as a discipline, with its share of all Ph.D. science graduates falling steadily from 15.6% in 1970 to 9.9% in 2002.
However, a likely more meaningful interpretation is that the data trace solid growth for chemistry as a whole as its applications move beyond the classic discipline to an ever-widening range of endeavors. The percentage of all Ph.D. science graduates earning their degrees in either chemistry or a chemistry-related discipline has held at close to 24% since 1985. This is about the same level as in the early 1970s. And it represents recovery from a dip to just over 20% in the early 1980s.
What has happened to classic chemistry has parallels with the experience of many inner cities in the U.S. over recent decades. Although their populations have declined, the surrounding urban areas they have engendered--and of which they remain the intellectual and spiritual core--have grown substantially.
The total of 19,485 Ph.D. graduates in all sciences in 2002 was only marginally higher than the 19,237 in 1992. Over this span, there was growth only in the biological and social sciences. For chemistry, physics, and mathematical/computer sciences, there were dips of 13.2%, 19.9%, and 10.3%, respectively.
DEFINITIONS. NSF organizes its data on Ph.D. science and engineering graduates into 200 categories, disciplines, and subdisciplines. Chemistry graduates are defined by NSF as those with degrees in analytical, inorganic, medicinal/pharmaceutical, nuclear, organic, physical, polymer, theoretical, and general and other chemistry.
For the purposes of this article, C&EN defines chemistry-related graduates as those earning Ph.D.s in the categories identified by NSF as biochemistry, geochemistry, chemical engineering, molecular biology, materials science, atmospheric physics and chemistry, atomic and molecular physics, and soil sciences, which includes soil chemistry. The chemical engineering category includes both petroleum and polymer engineers.
Some of these fields are unarguably subspecies of chemistry. Practitioners of some of the others may well not consider themselves primarily as chemists. But all of these fields have an underlying base in chemistry. Today, they attract graduate students who, 30 years ago, would likely have become classic chemists.
WOMEN. A sweeping change throughout all the sciences over the past generation has been the increase in the percentage of Ph.D. degrees earned by women. For all the sciences combined, it has grown from 11.3% of the 1970 class to 34.2% in 1992 and on up to 42.4% for 2002.
Growth in absolute terms has been most striking in psychology, from 23.5% in 1970 to 66.7% in 2002, and in sociology, from 18.4% to 61.1%. The gain has also been very large for the biological sciences, from 15.3% to 44.7%.
For chemistry, the increase has been from 8.1% women graduates in 1970 to 33.6% in 2002. Over the same period, women have come from nowhere in chemical engineering, 0.5%, to 25.0%. For all engineering, the gain has been from 0.4% to 17.5%. Trailing the field is physics with a 32-year gain for women of 2.7% to 15.8%.
Of the chemistry-related fields, molecular biology had the highest percentage of women in its 2002 graduating class, 43.4%. Atomic and molecular physics had the lowest, 13.6%.
Among the subdisciplines of classic chemistry, medicinal/pharmaceutical chemistry had the highest percentage of women in its 2002 class, at 39.4%. This was followed by analytical chemistry, at 37.9%. The lowest was organic, at 27.5%.
Further gains for women at the Ph.D. level appear inevitable. One reason is the enormous and still-evolving shift in the composition of bachelor's-level graduating classes. In 1970, women earned 43% of bachelor's degrees awarded in all fields. By 2001, the latest year for which data are available, this number was up to 57%. While the number of male graduates was growing modestly from 451,000 in 1970 to 532,000 in 2001, the number of female graduates soared from 341,000 to 712,000.
MEN. Where have the men gone? This is a legitimate question when it comes to science Ph.D.s, especially in chemistry.
In 1971, a record 13,525 men, as well as 1,926 women, earned Ph.D. degrees in science. For the 2002 class, the number of men was a substantially lower 11,220, whereas women graduates had advanced to 8,265. Overall growth for the period was from 15,451 to 19,485, with 2,305 fewer men in 2002 than in 1971 and 6,339 more women.
For classic chemistry, the relative decline for men has been sharper, with 2,056 male graduates in 1970 and 1,276 in 2002. As noted, the decline for white male U.S. citizen graduates was even more precipitous: from an estimated 1,500 to 636.
At least some of the men apparently missing from the ranks of Ph.D. chemistry graduates may have earned degrees in related fields. The number of male graduates in the chemistry-related disciplines rose from 1,333 in 1970 to 1,853 in 2002.
This all means a less jarring decline for men: from a combined 3,389 chemistry and chemistry-related Ph.D. graduates in 1970 to 3,129 in 2002. Over the same period, these combined totals for women rose from 240 to 1,532.
MINORITIES. The racial and ethnic diversity of U.S. citizens earning chemistry Ph.D.s is increasing, but at a modest pace. In 1970, 96.6% of such graduates were non-Hispanic whites. Thirty-two years later, this number is down to 85.7%. The biggest gain has been for Asian-American citizens, up from 1.4% to 7.0%, a proportion larger than the approximately 4% of all U.S. citizens who are Asian.
Non-Hispanic blacks and Hispanics, each now more than 12% of the U.S. population, continue to be markedly underrepresented in chemistry, with 3.7% and 3.2%, respectively, of Ph.D. graduates in 2002. But this does represent some progress for blacks, who had an unusually low 1.0% of graduates as recently as 1992. Hispanics have been hovering around the 3% level for the past 10 years. Native Americans, a little less than 1% of the U.S. population, continue to earn somewhat less than 1% of chemistry Ph.D.s.
NON-U.S. CITIZENS. Between 1970 and 1994, the percentage of Ph.D. degrees in chemistry earned by non-U.S. citizens grew almost every year from an initial 15.4% to 41.7%. In absolute numbers, the gain was from 340 to 922. By 2002, this number had slipped back to 688, or 37.8%. Tightened visa and immigration regulations, triggered by security concerns, could bring a further decline.
Science as a whole is almost as dependent on foreign graduate students as is chemistry. In 2002, 32.2% of all science Ph.D.s were earned by noncitizens.
CHEMISTRY-RELATED. The growth over the years in the number of graduates in the chemistry-related disciplines has been driven primarily by molecular biology and materials science. Both were in their infancy in 1970, with 95 and 35 Ph.D. graduates, respectively, for a total of 130. In 2002, this total was at 980, with 617 in molecular biology and 363 in materials science.
The other two major chemistry-related disciplines, biochemistry and chemical engineering, were both fully established by 1970. Both have shown solid growth since then. For biochemistry, the increase is from 583 graduates in 1970 to 781 in 2002, with a high of 846 in 1993. For chemical engineering, it is from 445 to 705, with a high of 798 in 1996.
The other chemistry-related fields--atmospheric physics and chemistry, atomic and molecular physics, geochemistry, and soil science--are smaller. Their combined total of Ph.D. graduates was 233 in 1970 and 273 in 2002, with a high of 316 in 1994.
IMPACT OF CHANGES. Even large changes in the profile of those entering a population as large and inherently stable as the chemical profession still take a long time to significantly change the demographics of that entire population.
For example, according to ACS's annual salary and employment surveys of its members in the domestic workforce, today about 20% of Ph.D. chemists are women. Even if women from now on earned 50% of chemistry Ph.D.s every year and participated in the workforce at the same rate as men, it would still be another 30 years or so before 50% of working Ph.D. chemists were women. In reality it will take much longer. A 50% share of new graduates is likely still a decade away at the earliest.
TABLE 1 - CHEMISTRY AND RELATED FIELDS Total number of Ph.D. graduates in chemistry and chemistry-related fields is down 600 from the 1998 peak but still up by 1,000 over the past 30 years
TABLE 2 - SCIENCE GRADUATES BY FIELD Except for biological and social sciences, the number of science and
TABLE 4 - WOMEN IN SCIENCE Except for biological and social sciences, the number of science and engineering Ph.D. graduates was lower in 2002 than it was in 1992