David M. Bressoud, February 2011
In his address to the National Academy of Sciences in 2009 , President Obama reiterated a point that one hears repeatedly from our leaders both in government and in business: If the United States is to maintain a preeminent economic position in the world, then we must increase the number of scientists and engineers that we produce.
Scientists and engineers are usually lumped together in the STEM disciplines (Science, Technology, Engineering, and Mathematics). Taken collectively, the numbers are encouraging. The 2010 National Science Board’s report on Science and Engineering Indicators highlights a 33% increase in undergraduate STEM majors from 1993 to 2007 .
STEM encompasses a wide variety of disciplines. Some of these, especially Psychology and the Biological Sciences, have been growing at admirable rates, 35% and 65% respectively over those fifteen years. As a mathematician, I am particularly interested in the ``math-intensive majors,’’ those that usually require mathematics beyond and building upon a full year of single variable calculus. For convenience, I will define these majors as three categories tracked by the US Department of Education: Engineering (not including engineering technologies), Physical Sciences (Physics, Chemistry, and Astronomy), and Mathematics and Statistics. For the math-intensive majors, the increases have been much more modest: 8.9% in Engineering, 19.9% in the Physical Sciences, and 4.7% in Mathematics and Statistics . (I have chosen not to include Computer Science partly because it is no longer clear how mathematically intensive this major is, but mostly because the number of its majors has oscillated wildly over the past three decades in response to perceived employment opportunities: from 11,000 in 1980 to 42,000 in 1986, down to 24,000 in the early ‘90’s, back up to 60,000 in the early years of this century, and down again to 38,000 in 2008, the most recent year for which I have data.)
Graph 1. Bachelors’ degrees in the math-intensive majors.
Looking back to 1980 (Graph 1), we see that the latest numbers, though representing an increase over the past fifteen years, are below the highest numbers of the past three decades. Engineering peaked at 77,154 in 1985 and was at 68,676 in 2008. The Physical Sciences reached their maximum of 24,052 in 1982 and by 2008 had fallen to 21,934. Mathematics and Statistics climbed to 16,489 in 1987 but stood at 15,192 in 2008. 
Graph 2. Bachelors’ degrees in math-intensive majors as a percentage of all bachelors’ degrees.
A more discouraging picture is conveyed by the percentage of bachelors’ degrees in the math-intensive majors (Graph 2) . The past three decades have seen very strong growth in the number of students going to and graduating from college. A fairly stable production of students in math-intensive fields means that, as a percentage of all college graduates, they have steadily declined. This is not particularly surprising. The high school achievements of those who today choose to major in math-intensive fields are such that they would have been college-bound thirty years ago. What is disappointing is that we have not appreciably increased the percentage of high school graduates who are prepared for and desire to pursue math-intensive majors. What is worrying is that the math-intensive majors are becoming increasingly marginalized within our colleges and universities
Graph 3. Population of 20–24 year olds. Estimated data from 2009 to 2025.
The most accurate measure of how effectively we are directing students to math-intensive majors is to compare the number of majors in these fields to the total population of 20–24 year olds. Graph 3 shows a fairly strong growth in the size of the US population within this age range over the past decade and reveals the long decline from 1980 to 1997 as the last of the bulge from the baby boom passed through our colleges. 
Most of our math-intensive majors are traditional college students in the sense that they go directly from high school to univesity, reflected in the fact that while 71% of full-time students enrolled in 4-year undergraduate programs are under 25, for math-intensive majors, the percentages are: Engineering, 83%; Physical Sciences, 79%; Mathematics and Statistics, 81%.
Graph 4. Bachelor’s degrees in math-intensive majors relative to number of 20–24 year olds.
If we consider the number of bachelors’ degrees earned in math-intensive majors relative to the total number of 20–25 year-olds (Graph 4), we see that there has been no growth over the past thirty years. In fact the percentages in 2008 were all within 0.004 percentage points of the average percentage from 1980 through 2008.
The past thirty years have seen some oscillation about the mean, but absolutely no net growth in the percentage of young people who choose to pursue math-intensive majors. Multiplying the percentages of Graph 4 by five to account for the fact we are covering ages that span five years, we see that about 1.6% of the population earns a degree in Engineering, 0.5% in the Physical Sciences, and 0.3% in Mathematics or Statistics. The combined total percentage has ranged from a low of 2.2% in 1980–81 and again from 2001 to 2003 to a high of 2.7% in 1985–87 and again in 1996–97.
As explained in my Launchings column of November, 2010 , this oscillation is largely explained by the unemployment situation at the time students enter college. High unemployment leads to high numbers of math-intensive majors four to five years later. Low unemployment produces low numbers of math-intensive majors. Unemployment peaked in 1982 and again in 1992. It fell below 5% in 1997 for the first time since 1973. The 2008 spike in unemployment led to an immediate and dramatic increase in the number of entering students intending to major in engineering. While this is certain to drive up the percentage of the population earning math-intensive majors, it is unlikely that this spike will have a more long-term effect than past peaks in unemployment.
Both the good and bad news is the remarkable stability of the number of students who choose to major in these math-intensive fields. It is nice to know that the numbers are not declining. But if we really do need to produce more scientists and engineers, then something fundamental needs to change.
 Barack Obama. 2009. Remarks by the President at the National Academy of Sciences Annual Meeting. April 27, 2009. www.whitehouse.gov/the_press_office/Remarks-by-the-President-at-the-National-Academy-of-Sciences-Annual-Meeting
 National Science Board. Science and Engineering Indicators: 2010. National Science Foundation. Arlington, VA. www.nsf.gov/statistics/seind10/
 NSB. 2010. Appendix Table 2-12 to Science and Engineering Indicators: 2010. www.nsf.gov/statistics/seind10/appendix.htm
 National Center for Education Statistics. Data collected from the Digest of Education Statistics from 1990 through 2009. nces.ed.gov/Programs/digest/
 based on US Population projections, www.census.gov/population/www/projections/summarytables.html and historical data.
 National Center for Education Statistics. 2010. Digest of Education Statistics: 2009. Table 232. nces.ed.gov/pubsearch/pubsinfo.asp?pubid=2010013
 David Bressoud. 2010. The Benefits of High Unemployment. Launchings. November, 2010. www.maa.org/columns/launchings/launchings_11_10.html
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David Bressoud is DeWitt Wallace Professor of Mathematics at Macalester College in St. Paul, Minnesota, and Past-President of the MAA. You can reach him at email@example.com. This column does not reflect an official position of the MAA.