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. 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 (table
U.S. federal occupation data classify workers by the activities or tasks they primarily perform in their jobs. The Occupational Employment Statistics (OES) survey administered by the Bureau of Labor Statistics (BLS) relies on employers to classify their workers using standard occupational definitions. National Science Foundation (NSF) and Census Bureau occupational data in this chapter come from surveys in which individuals (NSF) or members of their household (Census Bureau) supplied information about job titles and work activities. With this information, jobs can be coded into standard occupational categories. Differences between employer- and employee-provided information can affect the content of occupational data.
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 degree level of knowledge and education in S&E fields. A second category of occupations, S&E-related occupations, also requires some S&E knowledge or training, but not necessarily as a required credential for being hired 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 technical writers who edit scientific publications and salespeople who sell specialized research equipment to chemists and biologists. The NSF occupational classification of S&E, S&E-related, and non-S&E occupations appears in table
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 definition.
In this chapter, the narrow classification of S&E occupations is sometimes expanded to include S&E technicians, computer programmers, and S&E managers. This broader grouping is referred to here as STEM occupations.
The pool of S&E workers can also be identified by 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 seek such jobs if they do not currently hold them. However, a focus on people with relevant educational credentials also includes individuals who hold jobs that are not generally identified with S&E and who are not likely to seek S&E jobs in the future. Furthermore, workers with degrees in S&E may not have kept up to date with 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.
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, which we refer to in this report as 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. A recent survey provides clues to how college-educated Americans understand job-related technical expertise. (See sidebar, "Technical Expertise on the Job.")
In the most recent estimates, the U.S. S&E workforce (defined by occupation) totaled between 4.8 million and 6.4. million people (table
The 2003 SESTAT surveys provide a recent estimate for a different assessment of S&E work—whether workers believe their 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 workers in S&E occupations and 11.9 million whose highest degree was in an S&E field.
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 seven decades using Census Bureau data. The number of workers in S&E occupations grew from about 182,000 in 1950 to 5.4 million in 2009. This represents an average annual growth rate of 5.9%, much greater than the 1.2% 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 6.6 million (a 6.1% growth rate) (figure
In each decade, the growth rate of S&E occupations exceeded that of the total workforce (figure
Recent OES employment estimates for workers in S&E occupations indicate that the S&E workforce has remained steady while the total workforce has declined. The OES estimate was 5.5 million in May 2010, compared to 5.6 million in May 2007. The total workforce declined from 134 million to 127 million in this time frame. The broader STEM aggregate (including technicians, S&E managers, etc.) also remained relatively steady at 7.4 million in May 2010, compared to 7.6 million in May 2007. OES projections for 2008 to 2018 are that S&E occupations will 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 rate than employment in S&E jobs (figure
This growth in the S&E labor force was possible largely because of 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 educations, and (3) the relatively small proportion of scientists and engineers retiring from the S&E labor force. 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 NRC 2010 and NSB 2003).
Workers in S&E occupations have undergone more formal education than the general workforce (figure
Technical issues related to occupational classification may inflate the estimated size of the nonbaccalaureate S&E workforce. Even so, these data indicate that many individuals enter the S&E workforce with marketable technical skills from technical or vocational schools (with or without earned associate's degrees) or college courses, and many acquire these skills through workforce experience or on-the-job training. In information technology, and to some extent in other occupations, employers frequently use certification exams, not formal degrees, to judge skills. (See "Who Performs R&D?" and the discussion in chapter 2.)
Among individuals with at least a bachelor's degree who work in S&E occupations, a large proportion (88%) have at least one S&E degree, and 75% have S&E degrees only (table
S&E degree holders work in all manner of jobs. For example, they work in S&E-related jobs such as health occupations (1.4 million workers) or in S&E managerial positions (367,000 workers), but they also hold non-S&E jobs such as college and precollege teachers in non-S&E areas (655,000 workers) or work in social services occupations (634,000 workers) (appendix table
In 2008, 6.3 million workers whose highest degree was in an S&E field did not work in an S&E occupation. Some 1.3 million worked in S&E-related occupations, while 5.1 million worked in non-S&E jobs. The largest category of non-S&E jobs was management and management-related occupations, with 1.5 million workers, followed by sales and marketing occupations, with 882,000 workers (appendix table
Only about 38% of college graduates whose highest degree is in an S&E field work in S&E occupations (figure
By field, holders of degrees in computer sciences and mathematics and engineering most often work in the broad occupation group in which they were trained (53% and 50%, respectively). S&E doctorate holders more often work in an S&E occupation similar to their doctoral field (55%) compared with individuals whose highest degree is an S&E bachelor's (23%) (appendix table
Most individuals with S&E highest degrees who work in S&E-related or non-S&E occupations do not see themselves as working entirely outside their field of degree. Rather, most indicate that their jobs are either closely (34%) or somewhat (33%) related to their degree field (table
Workers with more advanced S&E education more often do work that is at least somewhat related to their field of degree. Up to 5 years after receiving their degrees, 96% of S&E doctorate holders say that they have jobs closely or somewhat related to their degree field, compared with 92% of master's degree holders and 75% of bachelor's degree holders (figure
The stronger relationship between S&E jobs and S&E degrees at higher degree levels holds at all career stages, as seen in comparisons among groups of bachelor's, master's, and doctoral degree holders at comparable numbers of years since receiving their degrees. However, for each group, the relationship between job and field of degree becomes weaker over time. There are many reasons for this decline: individuals may change their career interests, gain skills in different areas, take on general management responsibilities, forget some of their original college training, or even find that some of their original training has become obsolete. Against this background, the career-cycle decline in the relevance of an S&E degree appears modest.
The loose relationship among jobs, degrees, and individuals' perceptions of the expertise they need to do their work can be seen in figures