SCIENCE & ENGINEERING INDICATORS

The Science and Engineering Labor Force report uses a variety of data sources, including, but not limited to, the National Center for Science and Engineering Statistics (NCSES) Scientists and Engineers Statistical Data System (SESTAT), National Survey of College Graduates (NSCG), Survey of Doctorate Recipients (SDR), Survey of Earned Doctorates (SED), and Survey of Graduate Students and Postdoctorates in Science and Engineering (GSS); the U.S Census Bureau’s American Community Survey (ACS); the Occupational Employment Statistics (OES) survey administered by the Bureau of Labor Statistics (BLS); the Current Population Survey (CPS) sponsored jointly by the Census Bureau and BLS; and the U.S. Department of State Nonimmigrant Visa Statistics. Different sources cover different segments of the population and different levels of detail on the various topics (Table SA3-1). Although data collection methods and definitions can differ across surveys in ways that affect estimates, presenting data from different sources facilitates a more accurate and comprehensive picture of the very specialized S&E workforce. Long-term trends, international trends, and comparisons of S&E and non-S&E workers are discussed in the report when the suitable data are available.

The data from NCSES within National Science Foundation (NSF) provide detailed employment, education, and demographic information for adult scientists and engineers under age 76 residing in the United States. Scientists and engineers are defined as individuals who have a bachelor’s level or higher degree in science and engineering (S&E) or S&E-related fields or who have a non-S&E degree at the bachelor’s level or higher and are working in S&E or S&E-related occupations. Unless otherwise noted, the report uses the term scientists and engineers to refer to this broad definition and the term college graduates to refer to the population with at least a bachelor’s degree. The data available on scientists and engineers are collected by two large demographic and workforce surveys of individuals conducted by NCSES: the NSCG and SDR.

The NSCG and SDR provide the most comprehensive information about the size and characteristics of the S&E labor force. Because the NSCG covers the entire population of college graduates residing in the United States, this survey provides information on individuals educated or employed in S&E fields as well as those educated or employed in non-S&E fields. Whereas NSCG data cover the general college-educated population, the SDR data provide information on scientists and engineers who earned their research doctoral degree in a science, engineering, or health (SEH) field from a U.S. academic institution. The SDR is a biennial survey that has been conducted since 1973; it is a unique source of information on educational and occupational achievements and career movements of the nation’s doctoral scientists and engineers. More information on the NSCG and SDR are available at https://www.nsf.gov/statistics/srvygrads/ and https://www.nsf.gov/statistics/srvydoctoratework/.

The S&E Labor Force Report uses data from the Census Bureau to analyze the growth in the S&E workforce since 1960 and long-term unemployment trends. The types of occupations categorized as S&E have changed over time since 1960 as the economy has become more knowledge based and technological, and new occupations have been created as a result. See Table SA3-2 for a list of the occupations included in each year analyzed in the report.

Similarly, occupation codes have changed when defining S&E workers for the purposes of analyzing long-term employment trends. Table SA3-3 and Table SA3-4 shows the names and codes of the occupations included in each year analyzed in the report.

We define the skilled technical workforce using a combination of occupation designations from NCSES and from work conducted on behalf of the National Academies Board on Science, Technology, and Economic Policy (“the Academies”) for individuals whose educational attainment levels are less than a bachelor’s degree. Jonathan Rothwell’s 2015 publication “Defining Skilled Technical Work”—prepared for the Academies’ project on “The Supply Chain for Middle-Skilled Jobs: Education, Training, and Certification Pathways,” provides an approach to designating occupations that require significant scientific and technological expertise, but not necessarily a bachelor’s level degree or higher.^{​The Rothwell publication can be found at http://sites.nationalacademies.org/cs/groups/pgasite/documents/webpage/pga_167744.pdf.} This section will briefly explain the approach used for the Academies’ work and the NCSES occupations included in the definition used for the “Science and Engineering Labor Force” thematic report prepared for Indicators 2020.

Following the methodology of the Rothwell publication, this work uses skills-based data to identify occupations that rely upon workers with relatively high levels of scientific and technological skills and expertise. The U.S. Department of Labor sponsors data collected as part of the O*NET program. The O*NET program has created a content model capturing the distinguishing characteristics of an occupation and standardizing them into a measurable set of variables. Rothwell’s analysis, as outlined in the paper, utilizes the O*NET knowledge survey, which asks workers to rate the level of knowledge needed to perform their job across 33 distinct knowledge domains on a 1 to 7 scale. Using the O*NET version 19.0 and 2014 OES data, this report defines the occupations of the skilled technical workforce (STW) at the Standard Occupation Codes (SOC) level. The Rothwell criteria for inclusion of an occupation in the STW was a knowledge score in technical fields of at least 4.50 and a minority of individuals in that occupation with an educational attainment of a bachelor’s degree or higher.^{​OES employment data as published may have aggregations or suppressions. SOC codes that appear in the OES data but not the O*NET data were assigned imputed knowledge and education scores based on the mean of the values assigned to matching 5-digit codes. If matching 5-digit codes were not available, matching 4-digit codes were used.}

Using the occupation designations from the Rothwell approach in combination with occupations designated by NCSES as S&E or S&E-related occupations, the report uses ACS public use microdata (PUMS) to measure the size of this workforce. A crosswalk was produced between the SOC codes to the ACS occupation codes to enable aggregation up to the ACS occupation codes. This crosswalk is based on a crosswalk between SOC and occupation codes provided by the Census Bureau. SOC codes that did not have entries in the O*NET database were manually mapped to a similar field using the shared 5-digit codes. This resulted in multiple SOC codes being mapped to a single occupation code, so the OES employment data were used to create employment-weighted fractions of the O*NET scores for each SOC code.^{​This follows Rothwell’s method of imputation between 5- and 6-digit categories (see page 9 of http://sites.nationalacademies.org/cs/groups/pgasite/documents/webpage/pga_167744.pdf).} Table SA3-5 provides a list of the STW occupations and the employment of the STW in each occupation.