STEM Help Wanted: Methodology

To estimate the ratios of job postings in a field to unemployed people in that field, CTEq worked with the American Institutes for Research to collect data from two sources:

  • WANTED Analytics, which aggregates job postings from thousands of online job, newspaper and corporate websites and allows users to find job postings by occupational area.
  • The Bureau of Labor Statistics’ Current Population Survey, administered by the Census Bureau, which collects data on the number of unemployed people by occupational classification.

For each occupational classification we examined, we calculated the ratio between the average monthly number of new, unduplicated online job postings and the average monthly number of unemployed individuals. We calculated those averages over a span of three years beginning in March 2009 and ending in February 2012. Because monthly data were used for a three year period, it was not necessary to use seasonally adjusted data.

Defining Occupational Classifications

The occupational classifications were defined from the relevant occupational codes from the Bureau of Labor Statistics’ Standard Occupational Classification (SOC) system. WANTED Analytics classifies job postings using SOC codes; these codes were used to measure job postings within our chosen occupational classifications. The CPS has different occupational classifications, which changed during the sample period. We used the official crosswalks to ensure comparability in occupational classifications between the two data sources.1

Defining Science, Technology, Engineering and Mathematics (STEM) Occupations

To define STEM occupations, we adapted and expanded definitions from two widely-cited sources: Georgetown University’s Center on Education and the Workforce (CEW)2 and the Commerce Department’s Economics and Statistics Administration (ESA).3 We then added Healthcare Practitioner and Technical occupations that, according to our review of occupational data, require a substantial STEM background. Because healthcare is a major source of demand for STEM knowledge and skills, we felt our expanded definition would offer a more comprehensive picture of labor market demand for such knowledge and skills.

Our STEM definition includes all the occupations in the CEW definition: all Computer and Mathematical occupations (SOC 15-1111 through 15-2099); all Architecture and Engineering occupations (SOC 17-1011 through 17-3031); and Life and Physical Science Occupations (SOC 19-1011 through 19-2099; 19-4011 through 19-4099). Our definition also includes the three Management occupations ESA lists in its STEM definition: Computer and Information Systems Managers (SOC 11-3021); Architecture and Engineering Managers (SOC 11-9041); and Natural Sciences Managers (SOC 11-9121).

Finally, our definition includes occupations in the Healthcare Practitioner and Technical Occupations category (the precise mappings are provided below). We used the O*Net database, which describes occupations in terms of the knowledge and skills they require, to determine which of those occupations require substantial STEM knowledge and skills.4

 

Definition of STEM Occupations

 

SOC Code

Census Code

Management Occupations

Computer and Information Systems Managers

11-3021

0110

Architectural and Engineering Managers

11-9041

1300

Natural Sciences Managers

11-9121

0360

Computer and Mathematical Occupations

All Computer and Mathematical Occupations

15-1111 through 15-2099

1005 through 1240

Architecture and Engineering Occupations

All Architecture and Engineering Occupations

17-1010 through 17-3031

1300 through 1560

Life and Physical Science Occupations

All Life and Physical Science Occupations

19-1010 through 19-2099; 19-4011 through 19-4090

1600 through 1760; 1900 through 1965

Healthcare Practitioners and Technical Occupations

Chiropractors

29-1011

3000

Dentists

29-1020

3010

Dietitians and nutritionists

29-1031

3030

Optometrists

29-1041

3040

Pharmacists

29-1051

3050

Physicians and surgeons

29-1060

3060

Physician assistants

29-1071

3110

Podiatrists

29-1081

3120

Audiologists

29-1181

3140

Occupational therapists

29-1122

3150

Physical therapists

29-1123

3160

Radiation therapists

29-1124

3200

Respiratory therapists

29-1126

3220

Veterinarians

29-1131

3250

Registered nurses

29-1141

3255

Nurse practitioners

29-1171

3258

Clinical laboratory technologists and technicians

29-2010

3300

Diagnostic related technologists and technicians

29-2030

3320

Health practitioner support technologists and technicians

29-2050

3420

Licensed practical and licensed vocational nurses

29-2061

3500

Opticians, dispensing

29-2081

3520

Other healthcare practitioners and technical occupations

29-9000

3540

 

1 http://www.bls.gov/cps/cpsoccind.htm.
2 A.P. Carnevale, N. Smith, & M. Melton, STEM, Washington, DC: Georgetown University Center on Education and the Workforce, 2011.
3 D. Langdon, G. McKittrick, D. Beede, B. Khan, & M. Doms, “STEM: Good Jobs Now and for the Future,” ESA Issue Brief #03-11, Washington, DC: U.S. Department of Commerce, 2011.
4 O*Net is a service of the Department of Labor Employment and Training Administration and is available at www.onetonline.org. Because some Census Department Occupation Codes comprise more than one SOC code, our analysis of healthcare occupations in O*Net could not in every instance reflect the level of occupational detail available in the BLS classification system.