Skip all navigation and go to page content

Chapter 3. Science and Engineering Labor Force

Scope of the S&E Workforce

Measures of the S&E Workforce

The terms scientist and engineer can include very different sets of workers. This section presents three types of measures that can be used to estimate the size and describe the characteristics of the U.S. S&E labor force.[1] Different categories of measures are better adapted for addressing some questions than others, and not all general population and workforce surveys include questions in each category.

U.S. federal occupation data classify workers by the activities or tasks they primarily perform in their jobs. The Bureau of Labor Statistics' (BLS's) Occupational Employment Statistics (OES) survey collects data that rely on employers to classify their workers using standard occupational definitions. Census Bureau and National Science Foundation (NSF) occupational data in this chapter come from surveys in which individuals supplied information about job titles and/or work activities. This information enables jobs to be coded into standard occupational categories.

Although there is no standard definition of an S&E occupation, NSF has developed a widely used set of occupational categories that it calls S&E occupations. These occupations are generally associated with a bachelor's level of knowledge and education in S&E fields. A second set of occupations, S&E-related occupations, also require some S&E knowledge or training, but not necessarily as a required credential or at the bachelor's degree level. Examples of such occupations are S&E technicians or managers of the S&E enterprise who may supervise people working in S&E occupations. Other occupations, although classified as non-S&E, may include individuals who use their S&E technical expertise in their work. Examples include salespeople who sell specialized research equipment to chemists and biologists and technical writers who edit scientific publications. The NSF occupational classification of S&E, S&E-related, and non-S&E occupations appears in table 3-1 .

Other general terms, including science, technology, engineering, or mathematics (STEM), science and technology (S&T), and science, engineering, and technology (SET), are often used to designate the part of the labor force that works with S&E. These terms are broadly equivalent and have no standard meaning.

In this chapter, the narrow classification of S&E occupations is sometimes expanded to include S&E technicians, computer programmers, S&E managers, and a small number of non-health S&E-related occupations such as actuary and architect. This broader grouping is referred to here as STEM occupations.

The pool of S&E workers could also be identified in terms of educational credentials. Individuals who possess an S&E degree, whose highest degree is in S&E, or whose most recent degree is in S&E may be qualified to hold jobs that require S&E knowledge and skills and may choose to seek such jobs if they do not currently hold them. However, a focus on people with relevant educational credentials includes individuals who do not hold jobs that are generally identified with S&E and are not likely to seek them in the future. Workers with degrees in S&E may not have maintained current knowledge of the fields in which they were trained, may lack interest in working in jobs that require skills associated with S&E education, or may have advanced in their careers to a point where other skills have become more important.

S&E Technical Expertise
The S&E workforce may also be defined by the expertise required to perform a job or the extent to which job requirements are related to formal training in S&E. Many people, including some outside S&E occupations or without S&E degrees, report that their jobs require at least a bachelor's degree level of technical expertise in engineering, computer sciences, mathematics, the natural sciences, or social sciences (S&E technical expertise). Unlike defining the S&E workforce by occupational groupings or educational credentials, defining it by the use of technical knowledge, skills, or expertise involves assessing the content and characteristics of individual jobs. However, it also involves asking survey respondents to make a complex judgment about their jobs and apply a criterion that they are likely to interpret differently.[2]

Size of the S&E Workforce

Defined by occupation, the U.S. S&E workforce totaled between 4.3 million and 5.8 million people in 2006 (table 3-2 ). Those in S&E occupations who also had bachelor's degrees were estimated at between 4.3 million (Census Bureau 2007) and 5.0 million (NSF, Division of Science Resources Statistics [SRS], Scientists and Engineers Statistical Data System [SESTAT]).[3] SESTAT's 2006 estimates for individuals with an S&E degree at the bachelor's level or higher (16.6 million) or whose highest degree was in S&E (12.4 million) were substantially higher than the number of current workers in S&E occupations. Many of those whose highest degree is in S&E reported that their job, although not in an occupation classified as S&E, was closely or somewhat related to their highest degree (1.95 million closely related and 2.02 million somewhat related). Counting these people, along with those in S&E occupations, as part of the S&E workforce increases by 80% the size of the estimate by occupation alone.

The 2003 SESTAT surveys provide the most recent estimate for a different subjective assessment of S&E work—whether jobs require technical expertise at the bachelor's degree level or higher in S&E fields. According to these surveys, 12.9 million bachelor's degree holders reported that their jobs required at least this level of expertise in one or more S&E fields. This contrasts with 2003 SESTAT estimates of 4.8 million in S&E occupations and 11.9 million whose highest degree is in an S&E field.

Growth of the S&E Workforce

However defined, the S&E workforce has for decades grown faster than the total workforce. Defined by occupation, growth in the S&E workforce can be examined over nearly 6 decades using Census Bureau data. (For a discussion of longer periods, see the sidebar "Scientists Since Babylon.") The number of workers in S&E occupations grew from about 182,000 in 1950 to 5.5 million in 2007. This represents an average annual growth rate of 6.2%, nearly 4 times the 1.6% growth rate for the total workforce older than age 18 during this period. The somewhat broader category of S&T occupations grew from 205,000 to 6.5 million (figure 3-1 ).

In each decade, the growth rate of S&E occupations exceeded that of the total workforce (figure 3-2 ). During the 1960s, 1980s, and 1990s, the difference in growth rates was very large (about 3 times the rate for the total labor force). It was smallest during the slower growth period of the 1970s and between 2000 and 2007. S&E occupational employment has grown from 2.6% of the workforce in 1983 to 4.3% of all employment in 2007 (figure 3-3 ).

Recent OES employment estimates for workers in S&E occupations indicate that the S&E workforce is continuing to grow faster than the total workforce (see table 3A in sidebar "Scientists Since Babylon"). The OES estimate was 5.6 million in May 2007, up 9.9% from the May 2004 total of 5.1 million. This implies an average annual growth rate of 3.2%, about double the 1.6% average annual increase in employment in all occupations. During the same period, the broader STEM aggregate (including technicians, S&E managers, etc.) reached 7.6 million in May 2007 but grew at an average annual rate of 2.2%—slower than S&E occupations because of employment declines for both technicians/programmers and S&E managers. OES projections are that S&E occupations will continue to grow at a faster rate than the total workforce. (See sidebar, "Projected Growth of Employment in S&E Occupations.")

Between 1980 and 2000, although the number of S&E degree holders in the workforce grew more than the number of people working in S&E occupations, degree production in all broad categories of S&E fields rose at a slower pace than employment in S&E jobs (figure 3-4 ; see chapter 2 for a fuller discussion of S&E degrees). During this period, S&E employment grew from 2.1 million to 4.8 million (4.2% average annual growth), while total S&E degree production increased from 526,000 to 676,000 (1.5% average annual growth). Except for mathematics, computer sciences, and the social sciences, the growth rate for advanced degrees was higher than for bachelor's degrees.

This growth in the S&E labor force was largely made possible by the following three factors: (1) increases in U.S. S&E degrees earned by both native and foreign-born students who entered the labor force, (2) temporary and permanent migration to the United States of those with foreign S&E education, and (3) the relatively small proportion of scientists and engineers leaving the S&E labor force because they had reached retirement age. Many have expressed concerns about the effects of changes in any or all of these factors on the future of the U.S. S&E labor force (see NSB 2003).


[1] The standard definition of the term labor force includes the population that is employed or not working but seeking work (unemployed); other individuals are not considered in the labor force. 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] Despite the limitations of this subjective measure, variations among occupations in the proportions of workers who say they need this level of S&E technical expertise accord with common sense. For example, among doctoral level postsecondary teachers of physics, 99.7% said they needed at least a bachelor's level of knowledge in engineering, computer sciences, mathematics or the natural sciences, compared with 5% among doctoral level postsecondary teachers of English. Likewise, among the small numbers of S&E bachelor's degree holders whose occupation is "secretary/receptionist/typist," fewer than one in six reported that their job needed bachelor's level S&E expertise of any kind.
[3] Estimates of the size of the S&E workforce vary across the example surveys because of differences in the scope of the data collection (SESTAT surveys collect data from individuals with bachelor's degrees and above only); because of the survey respondent (SESTAT surveys collect data from individuals, OES collects data from establishments, and ACS collects data from households); or because of the level of detail collected on an occupation, which aids in coding. All of these differences can affect the estimates.

Science and Engineering Indicators 2010   Arlington, VA (NSB 10-01) | January 2010