U.S. S&E Workforce: Definition, Size, and Growth

1 The standard definition of the term labor force is a subset of the population that includes both those who are employed and those who are not working but seeking work (unemployed); other individuals are not considered to be in the labor force. Unless otherwise noted, when data refer only to employed persons, the term workforce is used. For data on unemployment rates by occupation, calculations assume that unemployed individuals are seeking further employment in their most recent occupation.

2 The SOC system is used by federal statistical agencies to classify workers into occupational categories for the purpose of collecting, calculating, and disseminating data. The Current Population Survey currently uses the 2010 Census occupational classification derived from the 2010 Standard Occupational Classification (SOC). The Census classification uses the same basic structure as the SOC but is generally less detailed. Detailed information on the SOC system is available at

3 As expected, this subjective measure—of the use of technical knowledge, skills, or expertise on the job—varies across occupations. For example, in 2015, among postsecondary teachers of chemistry, almost all those surveyed said that their job required at least a bachelor’s degree level of knowledge in engineering, computer sciences, mathematics, or natural sciences. Among postsecondary teachers of business commerce or marketing, 86% said that their job required at least this level of expertise in other fields such as health, business, or education. Among those with at least one degree at the bachelor’s level or higher in an S&E or S&E-related field whose occupation is secretary, receptionist, or typist, only about 5% said that their job required a bachelor’s degree level of knowledge in engineering, computer sciences, mathematics, or natural sciences; about 9% said that their job required at least a bachelor’s degree level of knowledge in social sciences; and 12% said that their job required at least a bachelor’s degree level of expertise in other fields such as health, business, or education.

4 Estimates of the size of the S&E workforce may vary across the different surveys because of differences in the scope of the data collection (the NSCG collects data from individuals with at least a bachelor’s degree); because of the type of survey respondent (the NSCG collects data from individuals, the OES survey collects data from employers, and the ACS collects data from households); or because of the level of detail collected on an occupation, which aids in classifying a reported occupation into a standard occupational category. For example, the NSCG estimate of the number of workers in S&E occupations includes postsecondary teachers of S&E fields; however, postsecondary teachers in ACS are grouped under a single occupation code regardless of field and are therefore not included in the ACS estimate of the number of workers in S&E occupations.

5 Among those with doctorates in an S&E field, life sciences and social sciences were the most common fields, followed by physical sciences, engineering, and computer and mathematical sciences.

6 The data on S&E employment levels for 1960 and 2015 are calculated using the Census Bureau’s 1960 Decennial Census and 2015 ACS microdata, respectively, adjusted by the Integrated Public Use Microdata Series (IPUMS) from the University of Minnesota’s Minnesota Population Center ( Occupational classification systems have changed over time, which limits the comparability of occupational counts over time. For example, computer occupations were not present in the occupational classification system used in 1960. For more information on the change in occupational classification systems, see Wyatt and Hecker (2006). S&E employment levels for 1960 and 2015 include workers at all education levels and do not include S&E postsecondary teachers. Although the 1960 Decennial Census data allow for separate identification of S&E postsecondary teachers, the 2015 ACS data aggregate all postsecondary teachers into one occupation code and therefore do not allow for separate identification of S&E postsecondary teachers. For 1960, the inclusion of S&E postsecondary teachers would increase the number of workers employed in S&E occupations to nearly 1.2 million. See Appendix Table 3-1 for a list of S&E occupations in the 1960 Decennial Census and 2015 ACS.

7 Many comparisons using Census Bureau data on occupations are limited to looking at all S&E occupations except postsecondary teachers because the Census Bureau aggregates all postsecondary teachers into one occupation code. NSF surveys of scientists and engineers and some BLS surveys collect data on postsecondary teachers by field.

S&E Workers in the Economy

1 The data on self-employment from NSCG include those who report being self-employed or employed by a business owner in either an unincorporated or incorporated business, professional practice, or farm. As a result, the data may capture both self-employed individuals in their own businesses and those whose principal employer is a business owner. This is a major reason why the NSCG estimate of self-employed workers in S&E occupations is higher than those from other surveys (e.g., the Census Bureau’s ACS).

2 The source of the federal S&E employment data is OPM’s Enterprise Human Resources Integration-Statistical Data Mart. Coverage is limited to federal civilian employees on pay status with certain exclusions. For information on specific exclusions and inclusions, see the coverage definition on OPM’s Federal Human Resources Data (FedScope) Web page:

3 Employment in the federal government is largely limited to those with U.S. citizenship. Many federal workers with S&E employment are in occupations that, nationwide, include relatively large concentrations of foreign-born persons, some of whom are ineligible for many federal jobs because they are not U.S. citizens.

4 This list does not include the National Institutes of Health, which is a part of the Department of Health and Human Services (HHS). S&E employment accounted for 19% of total HHS employment in 2016.

5 The establishments in this sector provide professional, scientific, and technical services to clients in a variety of industries as well as households. The services provided by S&E workers in this industry sector may include computer services; engineering and specialized design services; consulting services; research services; advertising services; and other professional, scientific, and technical services.

6 The other 10 activities are used to define four additional broad categories of primary or secondary work activities: teaching; management and administration; computer applications; and professional services, production workers, or other work activities not specified.

7 Social scientists were exceptions. In 2015, a larger proportion of social scientists with doctorates reported R&D activity than social scientists with master’s degrees; however, the difference in R&D activity rates between social scientists with doctorates and social scientists with bachelor’s degrees was not statistically significant.

8 Work-related training includes conferences and professional meetings only if the conference or meeting attendance also includes attending a training session. It does not include college coursework while enrolled in a degree program.

9 Although NSCG respondents were allowed to provide more than one reason for participating in work-related training, the data presented in this section are the most important reason for participating in such training.

S&E Labor Market Conditions

1 The Business Cycle Dating Committee of the National Bureau of Economic Research is generally the source for determining the beginning and end of recessions or expansions in the U.S. economy; see for additional information. Data on unemployment is from the Bureau of Labor Statistics: (accessed 14 August 2017). The unemployment rate rose from 9.7% in June 2009, the official end of the recession, until it peaked at 10.6% in January of 2010. It did not fall below the June 2009 rate again until April 2010.

2 The BLS civilian unemployment rate for persons 16 years and over, not seasonally adjusted, is available at (accessed 15 December 2016).

3 The CPS is the source of the official U.S. unemployment rate.

4 In this chapter, someone who is on tenure track but not yet tenured is referred to as “tenure-track” faculty.

5 Although the formal job title is often postdoc fellowship or research associate, titles vary among organizations. This chapter generally uses the shorter, more commonly used, and best understood name, postdoc. A postdoc is generally considered a temporary position that individuals take primarily for additional training—a period of advanced professional apprenticeship—after completion of a doctorate.

6 These estimates are new to this report and are based on the results of NSF’s ECDS. This pilot survey was developed to gather in-depth information about postdoc researchers and other early-career doctorate holders. The ECDS collects information related to educational achievement, professional activities, employer demographics, professional and personal life balance, mentoring, training and research opportunities, and career paths and plans for individuals who earned their doctorate in the past 10 years and are employed in an academic institution, a federally funded research and development center (FFRDC), or with one of the National Institutes of Health Intramural Research Programs (NIH IRP).

7 While these surveys do not cover postdocs working in industry and government for the most part, they do collect data on postdocs in FFRDCs, which may be run by for-profit or nonprofit businesses, and the NIH IRP, which is in the government sector.

8 These data are from the SED, which is administered to individuals receiving research doctoral degrees from all accredited U.S. institutions.

9 The data tables for the 2015 Survey of Graduate Students and Postdoctorates in Science and Engineering are available at (accessed 2 June 2017).

Age and Retirement of the S&E Workforce

1 The 2015 data on median age for the U.S. population are from the U.S. Census Bureau’s American FactFinder and are available at
. The 1993 data are available at (accessed 16 October 2017).

2 In 1994, the Age Discrimination in Employment Act of 1967 became fully applicable to universities and colleges, prohibiting the forced retirement of faculty at any age.

Women and Minorities in the S&E Workforce

1 In this chapter, American Indian or Alaska Native, Asian, black, Native Hawaiian or Other Pacific Islander, white, and more than one race refer to individuals who are not of Hispanic origin. Hispanics may be any race.

2 Salary differences represent estimated percentage differences in women’s reported full-time annual salary relative to men’s reported full-time annual salary as of February 2015. Coefficients are estimated in an ordinary least squares regression model using a natural log of full-time annual salary as the dependent variable. This estimated percentage difference in earnings differs slightly from the observed difference in median earnings by sex because the former addresses differences in mean earnings rather than median earnings.

3 Included are 20 NCSES-classified field-of-degree categories (out of 21 S&E fields), 38 NCSES-classified occupational categories (out of 39 categories), 6 NCSES-classified employment sector categories (out of 7), years since highest degree, and years since highest degree squared.

4 The estimates in Figure 3-31 for the last two models of the master's degree level, 4.2 and 3.6, respectively, are not significant at the 90% confidence level.

5 The regression analysis addresses major factors that affect differences in earnings but does not attempt to cover all possible sources of difference. For a more detailed discussion on the topic, see Blau and Kahn (2007), Mincer (1974), Polachek (2008), and Xie and Shauman (2003).

6 See Figures 6-B and 6-C in “Employment Status” from National Science Foundation, National Center for Science and Engineering Statistics (2017).

7 In addition to the education- and employment-related variables, the following indicators are included in wage regression models: nativity and citizenship, marital status, disability, number of children living in the household, geographic region (classified into nine U.S. Census divisions), and whether either parent holds a bachelor’s or higher level degree. The sex regression controls for racial and ethnic minority status, and the race and ethnicity regression controls for sex.

8 The estimates in Figure 3-31 for the last two models of the master's degree level, 4.2 and 3.6, respectively, are not significant at the 90% confidence level.

Immigration and the S&E Workforce

1 For information on high-skill migration worldwide, see Defoort (2008); Docquier and Rapoport (2012); Docquier, Lowell, and Marfouk (2009); and Docquier and Marfouk (2006).

2 For all types of temporary work visas, the actual number of individuals using them is less than the number issued. For example, some individuals may have job offers from employers in more than one country and may choose not to foreclose any options until a visa is certain.

3 This question is part of the SED, which is administered to individuals receiving research doctoral degrees from all accredited U.S. institutions. For information on the SED, see The information on plans to stay or definite commitments to stay reflects intentions within the year after graduation as reported by the doctorate recipients around their graduation date. Therefore, any changes in intentions after survey completion are not captured.

4 Many foreign recipients of U.S. doctorates who report that they plan to stay in the United States the year after graduation may do so using their student (F-1) visa and never obtain a new visa that would permit a longer stay. Student visas permit an additional 12-month stay in the United States after graduation if a student applies for optional practical training (OPT). OPT refers to paid or unpaid work that is performed at least 20 hours a week and that is related to a student’s field of study. Starting in May 2016, those earning a degree in STEM fields could apply for an extension of their OPT to a total of 36 months. Data from the Department of Homeland Security’s Student and Exchange Visitor Information System ( show that 68% of students with F-1 visas who completed a doctorate in any field between 1 November 2015 and 31 October 2016 had applied for OPT.

5 To reduce the standard error of the estimates, a 3-year average was used to calculate the long-term stay rates. For example, the 10-year stay rate was based on the proportion of the 2004, 2005, and 2006 cohorts who reported living in the United States in 2015.