Occupational Classification Systems: Analyzing the 2010 Standard 

Occupational Classification (SOC) Revision 

 

Alissa Emmel and Theresa Cosca 

Bureau of Labor Statistics 

2 Massachusetts Ave., NE 

Washington, DC 20212 

emmel.alissa@bls.gov

cosca.theresa@bls.gov

The 2010 Standard Occupational Classification (SOC) is a system for classifying all occupations in the U.S. economy. The 

term “occupation” refers to the “collective description of a number of individual jobs performed, with minor variations, in 

many establishments.”1

 Individual workers in an establishment perform a specific set of tasks that is largely dependent on 

factors such as the employment size and industry classification of that establishment, as well as the tasks performed by other 

workers in that same establishment. This combination of tasks makes up an individual worker’s job and while the exact 

group of tasks is often, but not always, unique to that worker, almost every job is similar to a number of other jobs. 

Occupational classification schemes organize millions of jobs into discrete groups based upon their similarities as determined 

by the scheme’s classification principles.2

The SOC system “is used by Federal statistical agencies to classify workers and jobs into occupational categories for the 

purpose of collecting, calculating, analyzing, or disseminating data.”3

 This paper discusses how a task-based system 

promotes consistency in the method used for classifying the 840 occupations in the 2010 SOC, and thus enhances 

comparability of data collected by various statistical agencies. It details the process used and the issues considered to revise 

the SOC system for 2010. The paper will also touch on the relation of the 2010 SOC to the International Labor 

Organization’s International Standard Classification of Occupations (ISCO). 

Types of Classification Systems 

The SOC is a hierarchical classification system, as opposed to a faceted classification system. A hierarchical system requires

only one overarching organizing principle, whereas a faceted classification scheme uses a number of separate hierarchies 

(facets) concurrently.4

 A faceted system can provide more information because each item is defined by multiple 

characteristics. Although faceted systems are often more voluminous, they also facilitate discovery of gaps in the system—

an advantage when designers strive to capture all possible variations of the classified items. Under the hierarchical system 

used by the SOC, the same occupational code is assigned to a Civil Engineer with a bachelor’s degree employed by a civil 

engineering services firm, as is assigned to a Civil Engineer with a master’s degree employed by a similar civil engineering 

services firm, and further, to a Civil Engineer with a bachelor’s degree in a nonresidential building construction firm. Under

a faceted system with three facets (work performed, educational level, and industry) each of these three workers would have a 

different code. 

Hierarchical systems can be either polyhierarchical or mono-hierarchical, depending on whether or not the classified items 

appear in multiple locations. In a polyhierarchical system, content is reused, therefore an occupation can be found in multiple 

places. For example, an occupation requiring expertise in both business and sales (such as fundraising) can be found in two 

places in the structure, under both sales and business. Further, if an individual’s occupation was “fundraising manager,” that

 

Acknowledgment: The authors thank Anne Louise Marshall, an economist formerly with the Bureau of Labor Statistics, 

Division of Occupational Employment Statistics, for her contribution to this paper. Any opinions expressed in this paper are 

those of the authors and do not constitute policy of the Bureau of Labor Statistics. 

1 Dictionary of Occupational Titles, Revised 4th edition, Vol. 1, p. xvii, (U.S. Department of Labor, Employment and Training Administration, 1991).

2Federal Register, Vol. 71, No. 94, p. 28538, (Office of Management and Budget, May 16, 2006).

3Federal Register, Vol. 74, No. 12, p. 3921, (Office of Management and Budget, January 21, 2009).

4

See Pavel Babikov, Oleg Gontcharov, and Maria Babikova, “Polyhierarchical Classifications Induced by Criteria Polyhierarchies and Taxonomy Algebra,” 

QNT Software Development, Inc., on the Internet at http://arxiv.org/ftp/cs/papers/0312/0312059.pdf (visited Jan. 4, 2010).
 

category could be found in three locations: sales, business, and management. The SOC is a mono-hierarchical system, under 

which each occupation is found in only one place. In addition, the categories in the SOC are exclusive, exhaustive, and the 

higher levels are completely described by the lower levels of aggregation. 

The classification principles determine the 

fundamental characteristics of the SOC. As 

shown in Figure 1, the exclusivity of the SOC 

occupations is explained in the first 

classification principle, “Each occupation is 

assigned to only one occupational category at 

the lowest level of the classification.” The 

principle of exhaustivity is demonstrated by the 

fourth coding guideline, “Workers who perform 

activities not described in any distinct detailed 

occupation in the SOC structure should be 

coded in an appropriate ‘All Other’ or residual 

occupation.” The inclusion of residual 

occupations ensures that all jobs can be 

captured by the SOC structure. (See Appendix 

A for the full list of SOC Classification 

Principles and Coding Guidelines.) 

Figure 1: Exclusivity and Exhaustivity

SOC Classification Principle 1 

The SOC covers all occupations in which work is performed for pay or 

profit, including work performed in family-operated enterprises by 

family members who are not directly compensated. It excludes 

occupations unique to volunteers. Each occupation is assigned to only 

one occupational category at the lowest level of the classification. 

SOC Coding Guideline 4 

Workers who perform activities not described in any distinct detailed 

occupation in the SOC structure should be coded in an appropriate 

“All Other” or residual occupation. These residual occupational 

categories appear as the last occupation in a group with a code ending 

in “9” and are identified by having the words “All Other” appear at the 

end of the title.

Yet even mono-hierarchical systems can have a plethora of occupations. The fourth edition of the Dictionary of 

Occupational Titles (DOT) listed 12,099 occupations. The vast level of detail in the DOT made it difficult to provide reliable

information for DOT occupations on a recurring, timely, and consistent basis. The ninth classification principle, new to the 

2010 SOC, requires that “for a detailed occupation to be included in the SOC, either the Bureau of Labor Statistics or the 

Census Bureau must be able to collect and report data on that occupation.”5

 This objective is not met if the categories 

created are too narrow, as in the DOT, where separate classifications were created for Tree Surgeon (408.181-010), Tree 

Trimmer (408.664-010), and Tree Pruner (408.684-018). Although there are slight differences in the work performed in each 

of these detailed occupations, there are also many similarities. All workers classified in these occupations “Cut away dead or

excess branches from trees or shrubs to maintain right-of-way for roads, sidewalks, or utilities, or to improve appearance, 

health, and value of tree.”6

 Therefore, following the principles and guidelines of the SOC, all of these types of workers are 

included in the SOC occupation, Tree Trimmers and Pruners (37-3013). 

Overview of the SOC Hierarchy 

In the 2010 SOC, as with the 2000 SOC, there are four levels of aggregation: major group, minor group, broad occupation, 

and detailed occupation. All occupations are clustered into 23 major groups (listed in Table 1), such as Business and 

Financial Operations Occupations (13-0000) or Healthcare Practitioner and Technical Occupations (29-0000). These major 

groups are broken down into occupationally-specific minor groups, such as Financial Specialists (13-2000) in Business and 

Financial Operations Occupations, or Health Diagnosing and Treating Practitioners (29-1000) in the Healthcare Practitioners 

and Technical Occupations major group. Minor groups, in turn, are divided into broad occupations, such as Credit 

Counselors and Loan Officers (13-2070) or Therapists (29-1120), which are further divided into detailed occupations, such as 

Credit Counselors (13-2071), or Exercise Physiologists (29-1128).

Each item in the hierarchy is designated by a six-digit code. The first two digits of the 2000 SOC code represent the major 

group; the third digit represents the minor group; the fourth and fifth digits represent the broad occupation; and the sixth digit 

represents the detailed occupation. Major group codes end with 0000 (e.g., 29-0000, Healthcare Practitioners and Technical 

Occupations), minor groups generally end with 000 (e.g., 29-1000, Health Diagnosing and Treating Practitioners), broad 

occupations end with 0 (e.g., 29-1120, Therapists), and detailed occupations end with a nonzero digit (e.g., 29-1123, Physical 

Therapists). The hyphen between the second and third digit is used only for presentation clarity.7

 

5Federal Register, January 21, 2009, p. 3924.

6

Standard Occupational Classification Manual 2000, p. 116, (Office of Management and Budget, October 2000).

7Federal Register, Vol. 64, No. 180, p. 53138, (Office of Management and Budget, September 30, 1999).
 

 

Table 1: 2010 SOC Major Groups 

Code Title Code Title 

11-0000 Management Occupations 33-0000 Protective Service Occupations 

13-0000 Business and Financial Operations Occupations 35-0000 

Food Preparation and Serving Related 

Occupations 

15-0000 Computer and Mathematical Occupations 37-0000 

Building and Grounds Cleaning and 

Maintenance Occupations 

17-0000 Architecture and Engineering Occupations 39-0000 Personal Care and Service Occupations 

19-0000 Life, Physical, and Social Science Occupations 41-0000 Sales and Related Occupations 

21-0000 Community and Social Service Occupations 43-0000 Office and Administrative Support Occupations 

23-0000 Legal Occupations 45-0000 Farming, Fishing, and Forestry Occupations 

25-0000 Education, Training, and Library Occupations 47-0000 Construction and Extraction Occupations 

27-0000 

Arts, Design, Entertainment, Sports, and Media 

Occupations 49-0000 

Installation, Maintenance, and Repair 

Occupations 

29-0000 

Healthcare Practitioners and Technical 

Occupations 51-0000 Production Occupations 

31-0000 Healthcare Support Occupations 53-0000 

Transportation and Material Moving 

Occupations 

55-0000 Military Specific Occupations 

Background on the SOC and the 2010 SOC Revision 

Prior to the development of the 2000 SOC, government statistical agencies that collected and reported occupational 

information did not all use a common classification system. In response to a need for such a system, in 1994 the Office of 

Management and Budget (OMB) chartered the Standard Occupational Classification Revision Policy Committee (SOCRPC), 

which was tasked with devising a uniform classification system. In carrying out this charge, OMB and the Committee issued 

several Federal Register notices. Based on comments in response to these notices, and four years of research by the 

SOCRPC and workgroups composed of members from more than fifteen government agencies, the SOCRPC and OMB 

developed and published the 2000 Standard Occupational Classification Manual.

In 2005, the Office of Management and Budget first met with a newly-formed Standard Occupational Classification Policy 

Committee (SOCPC) to initiate the formal 2010 SOC revision process. The first question the Committee addressed was the 

scope of the revision. The Committee determined to keep a major organizing principle used in the 2000 SOC, and classify 

occupations based on the type of work performed. As Levine, Salmon, and Weinberg noted for the 2000 revision, the 

SOCRPC considered four basic organizing principles for constructing the 2000 SOC. The first option, used in the 1980 SOC, 

was the type of work performed. The second option, used in the International Standard Classification of Occupations 

(ISCO), was education-based. The third option was to devise a skills-based system, and the fourth option was to use an 

economic-based system.8

Task-Based System 

The SOCPC decided that the underlying organizational concept, as presented in the classification principles for the 2010 

SOC system, should continue to be work performed. Therefore, workers with varying levels of skills, education, or 

experience performing the same tasks are classified in the same occupation in the SOC. The 2010 SOC system specifies both 

 

8

See Chester Levine, Laurie Salmon, and Daniel H. Weinberg, “Revising the Standard Occupational Classification system,” Monthly Labor Review, May 

1999, p. 37, on the Internet at http://www.bls.gov/opub/mlr/1999/05/art4full.pdf (visited Jan. 4 2010).
 

classification principles and coding guidelines, whereas the 2000 SOC only identified classification principles. Both were 

determined to be necessary because they serve different purposes. The classification principles form the basis on which the 

SOC system is structured and describe “how” and “why” occupations are classified in the 2010 SOC structure. The coding 

guidelines assist users in consistently assigning SOC codes to survey responses. The first coding guideline states “A worker 

should be assigned to an SOC occupation code based on work performed.”9

 

The SOCPC also considered, but ultimately rejected, other alternatives to the task-based system, such as skills or credentials. 

If a classification scheme is based on skill level, which of the multiple skill levels within an occupation should be used to 

classify the occupation? The difficulty in answering this question exemplifies the problematic nature of a classification 

scheme that is based upon determining a single skill level for an occupation. Classification principle 2 and coding 

guideline 2 mention skills, but in the context of work performed as the primary determinant of classification. In its official

response to the comment suggesting increased emphasis on credentials in the classification, the SOCPC stated that: 

The SOC classifies occupations based on work performed, therefore unless a specific credential is required 

in order to work in a position (as in the case of licensed occupations), possessing a credential may enhance 

an individual's skills or employability but is not always a requirement for employment in the occupation. 

Persons employed in most occupations include both those who do not possess certain credentials, as well 

as those who do, with significant variation by locality and employer. No good information exists on the 

number or share of people in occupations who possess credentials. Further, many credentials are for 

specific skill sets, not for occupations, and would not be germane in any case.

10

The SOCPC removed ‘‘credentials’’ from the criteria listed in the second classification principle used in the 2000 SOC due 

to the complexity, variability, and frequency of change in credential requirements. In particular: 

(1) There are many different types of credentials that apply to occupations–State occupational 

licensing, Federal occupational licensing, private sector occupational certifications, as well as 

certifications of particular skill sets that may apply to multiple occupations, such as certification in 

facility with a certain type of software, equipment, or safety or regulatory procedures. 

(2) Credentialing requirements vary not only from State to State, but may also vary by locality, by 

industry size class, or by firm. 

(3) There is no current data collection mechanism to obtain comprehensive information on 

occupational credentialing and keep it updated; therefore, it is not feasible to adequately factor in 

credentialing requirements when classifying or defining an occupation. 

(4) As technology and other requirements change, credentials change over time more rapidly than 

other variables and these changes could not be reflected in a classification that is to remain stable 

over a 5- to 10-year period–as attested to by the hundreds of Information Technology certifications 

that have come into existence during the last 5 to 10 years–the period during which the 2000 SOC 

was developed and put into use.11

The Review Process 

OMB and the SOCPC first requested public comment on the SOC revision for 2010 in the May 16, 2006 Federal Register. In

this notice, the Committee welcomed comments related to all aspects of occupational classification but specifically requested 

comments on the revised classification principles, the intention to retain the major group structure, and proposals on 

corrections or changes to existing occupations and for new detailed occupations. To carry out the bulk of the revision effort,

the committee created six work groups to review the comments received in response to the Federal Register notice. The 

review of the recommendations was guided by the classification principles, and all decisions were made by consensus. A 

second Federal Register notice soliciting comments on recommended changes to the occupational structure, classification 

principles, and coding guidelines was published on May 22, 2008. 

 

9Federal Register, Vol. 73, No. 100, p. 29932, (Office of Management and Budget, May 22, 2008).

10See Standard Occupational Classification Policy Committee, “Responses to comments on 2010 SOC,” on the Internet at 

http://www.bls.gov/soc/2010_responses/response_08-0897.htm (visited Jan. 4, 2010).

11Federal Register, May 16, 2006, p. 28537.
 

The SOCPC responded to the hundreds of comments received by creating new occupations, revising occupational titles, and 

changing the placement of individual occupations within the revised structure. An important question raised in one of these 

comments asked whether users could conclude that changes to the 2010 SOC structure stemmed from changes to the 2000 

SOC classification principles. However, because the changes made by the SOCPC were intended to clarify the existing 

principles, the substantive structural changes incorporated throughout the revised 2010 SOC can be attributed to 

technological advancements and actual changes in the nature or organization of work activities performed in the economy.12

What changed in the 2010 SOC 

In comparison to the 2000 SOC, the 2010 SOC realized a net gain of 19 detailed occupations, 12 broad occupations, and 1 

minor group. The 2010 SOC system contains 840 detailed occupations, aggregated into 461 broad occupations. In turn, the 

SOC combines these 461 broad occupations into 97 minor groups and 23 major groups. Of the 840 detailed occupations in 

the 2010 SOC, 359 remained the same as in 2000, 452 had definition changes, 21 had a title change only, and 9 had a code 

change without a change in the definition. Most of the definition changes (392) were editorial revisions that did not change 

occupational content. Therefore, no substantive change occurred in occupational coverage for more than 9 out of 10 detailed 

occupations in the 2010 SOC. 

As noted, the codes, titles, and definitions for many existing SOC occupations were changed. Sometimes occupational titles 

were changed to clarify occupational coverage or mitigate confusion. For example, Architectural Managers in the 2000 SOC 

were included in “Engineering Managers” (11-9041 in the 2000 SOC), but not specified in the SOC title. In the 2010 

structure, the title was changed to Architectural and Engineering Managers and the code 11-9041 was retained. 

There were 60 instances of a code change. In some cases, a code changed because a broad occupation was split. For 

example, Training and Development Specialists (13-1073) were formerly classified in the broad occupational group, Human 

Resources, Training, and Labor Relations Specialists (13-1070). However, in the 2010 SOC this detailed occupation appears 

under its own broad occupation group Training and Development Specialists (13-1150). In this case, the content of the 

occupation did not change, just its location in the structure. In other cases, the code changed because the content changed. 

For example, the 2010 code for Registered Nurses (29-1141) was modified to draw attention to a change in occupational 

content. The 2010 SOC was expanded to include three new detailed nursing occupations that were previously included with 

Registered Nurses: Nurse Anesthetists (29-1151), Nurse Midwives (29-1161), and Nurse Practitioners (29-1171). 

The vast majority of the changes, however, were editing changes. Some editing changes were relatively minor–correcting 

punctuation or changing a single word, for example. Other editing changes were more extensive and resulted in a complete 

re-writing of the definition. There were also 60 instances of revisions to definitions that affected occupational coverage. 

These 60 detailed occupations, which include the 24 new occupations denoted by an asterisk (*), can be found in 

Appendix B. Appendix B encompasses collapsed occupations, as well as 2010 occupations that resulted from a split. A table 

describing the types of changes made to all detailed occupations will be available on the SOC homepage at www.bls.gov/soc, 

along with other supporting materials. 

While it is not practical to discuss all of the changes incorporated in the 2010 SOC, this paper will highlight the two new 

renewable energy occupations and the consideration given to new “green” economic activities. There will be a further 

discussion of changes in the information technology occupations in the section that relates to the International Standard 

Classification of Occupations (ISCO). 

“Green” Occupations in the 2010 SOC 

The 2010 SOC contains two new detailed occupations related to renewable energy; Solar Photovoltaic Installers (47-2231) 

and Wind Turbine Service Technicians (49-9081). Solar Photovoltaic Installers assemble, install, or maintain solar 

photovoltaic (PV) systems that generate solar electricity. Wind Turbine Service Technicians inspect, diagnose, and repair 

wind turbines. Their maintenance work may include resolving electrical, mechanical, or hydraulic malfunctions. The 

SOCPC carefully analyzed over 80 unique suggestions regarding “green” occupations and considered these recommendations 

from the perspective of the SOC classification principles. The three classification principles most commonly cited in the 

rationales provided for the SOCPC’s decisions were: classification principle 1 which states that occupations are assigned to 

 

12See Standard Occupational Classification Policy Committee, “Responses to comments on 2010 SOC,” on the Internet at 

http://www.bls.gov/soc/2010_responses/response_08-0012.htm (visited Jan. 4, 2010).
 

only one occupational category, classification principle 2 which states that occupations are classified based on work 

performed, and classification principle 9 which relates to collectability.13

More specifically, classification principle 1 states “Each occupation is assigned to only one occupational category at the 

lowest level of the classification.” The SOCPC frequently found that the work performed by a proposed “green” job was 

already covered by the description of an existing SOC occupation. For example, a “Cellulose Insulation Installer” would be 

coded in 47-2131 “Insulation Workers, Floor Ceiling and Walls” because although the materials used may differ, the work 

performed is the same as the work performed by other Insulation Workers, who “line and cover structures with insulating 

materials.” The Occupational Information 

Network (O*NET) described some of these 

proposed green jobs as “Green Increased 

Demand Occupations” where the work context 

may change but the tasks themselves do not, 

or “Green Enhanced Skills Occupations” 

where the essential purposes of the occupation 

remained the same, but the skills, knowledge, 

or credentials have been altered.14 For 

examples of “green” job titles the SOCPC felt 

were already covered in the existing SOC 

structure, see Table 2. 

After extensive research, the SOCPC 

determined that the work performed by Solar 

Photovoltaic Installers and Wind Turbine 

Service Technicians was sufficiently distinct 

from the work performed in other occupations 

and would satisfy the collectability 

requirements of classification principle 9. According to a U.S. Energy Information Administration (EIA) report, “Strong 

growth in the U.S. photovoltaic (PV) industry continued in 2008. Total shipments of PV cells and modules increased more 

than 90 percent to nearly 1 million peak kilowatts.”15 In their 2009 International Energy Outlook, the EIA noted that solar 

power is one of the fastest-growing sources of renewable energy and its use is likely to increase in the future, and further, the 

U.S. Department of Energy indicated that “up to $87 million will be made available to support the development of new solar 

energy technologies and the rapid deployment of available carbon-free solar energy systems.”16 The American Wind Energy 

Association (AWEA) noted in their 2008 Annual Report that “in 2008, the U.S. wind energy industry brought online over 

8,500 megawatts (MW) of new wind power capacity, increasing the nation’s cumulative total by 50% to over 25,300 MW 

and pushing the U.S. above Germany as the country with the largest amount of wind power capacity installed.”17

Table 2: Examples of “Green” Job Titles and where they are included 

in the SOC 

“Green” Job Title SOC Code SOC Title 

Hybrid Vehicle Mechanic 49-3023 

Automotive Service 

Technicians and Mechanics 

Solar Photovoltaic 

Electrician 47-2111 Electricians 

Solar Photovoltaic 

Installation Supervisor 47-1011 

First-Line Supervisors of 

Constructions Trades and 

Extraction Workers 

Solar Thermal Installer 47-2152 

Plumbers, Pipefitters, and 

Steamfitters 

Sustainable Landscape 

Architect 17-1012 Landscape Architects 

Water Retrofitter 47-2152 

Plumbers, Pipefitters, and 

Steamfitters 

Wind Turbine Erector 47-2221 

Structural Iron and Steel 

Workers 

Currently there are 24 States (plus the District of Columbia) with a renewable portfolio standard (RPS), which is a State 

policy requiring electricity providers to obtain a minimum percentage of their power from renewable energy sources. Five 

other States have nonbinding goals for adoption of renewable energy instead of an RPS. “Together these States account for 

more than half of the electricity sales in the United States.”18

 The U.S. Department of Energy formed a Solar Energy 

Technologies Program (SETP) to focus on research, development, and deployment projects for renewable energy. The SETP 

Multi Year Program Plan released in April 2008 highlighted an expected increase in the global and domestic growth rate of 

the photovoltaic market. This report noted “the most optimistic of these forecasts calls for a 51% compound annual growth 

rate in worldwide solar installations through 2011. This evidence points to the emergence of a worldwide industry at a 

 

13See Standard Occupational Classification Policy Committee, “Responses to comment on 2010 SOC,” on the Internet at 

http://www.bls.gov/soc/2010_responses/response_08-0492_08-0762_08-1157.htm (visited Jan. 4, 2010).

14See Erich C. Dierdorff, Jennifer J. Norton, Donald W. Drewes, Christina M. Kroustalis, David Rivkin and Phil Lewis, “Greening of the World of Work: 

Implications for O*NET®-SOC and New and Emerging Occupations,” on the Internet at http://www.onetcenter.org/dl_files/Green.pdf (visited Jan. 4, 2010).

15U.S. Department of Energy, Energy Information Administration, “Solar Photovoltaic Cell/Module Manufacturing 

Activities 2008,” on the Internet at http://www.eia.doe.gov/cneaf/solar.renewables/page/solarreport/solarpv.pdf (visited Jan. 4, 2010).

16U.S. Department of Energy, Oct. 8, 2009 press release, “DOE Announces $87 Million in Funding to Support Solar Energy Technologies,” on the Internet 

at http://www.energy.gov/news2009/8115.htm (visited Jan. 4, 2010).

17American Wind Energy Association, “Annual Wind Industry Report, Year Ending 2008,” on the Internet at 

http://www.awea.org/publications/reports/AWEA-Annual-Wind-Report-2009.pdf (visited Jan. 4, 2010).

18U.S. Department of Energy “States with Renewable Portfolio Standards, May 2009” on the Internet at 

http://apps1.eere.energy.gov/states/maps/renewable_portfolio_states.cfm (visited Jan. 4, 2010).
 

‘jumping off’ point.”19 The American Wind Energy Association reported on October 20, 2009 that the U.S. wind energy 

industry installed 1,649 megawatts (MW) of new power generating capacity in the third quarter, an amount higher than either 

the 2nd quarter of 2009 or the 3rd quarter of 2008.20 According to the Occupational Outlook Quarterly “electricity generated 

from renewable sources is one of the fastest growing segments of the electric power industry.”21

Classification principle 9 indicates that “For a detailed occupation to be included in the SOC, either the Bureau of Labor 

Statistics or the Census Bureau must be able to collect data on that occupation.”22 Collectability was frequently a concern in 

evaluating proposals for new occupations. In some instances, the quantity of workers performing “green” tasks as their 

primary activity was not substantial enough to support a new detailed occupation. For other recommendations, the 

recommended occupations were so dispersed throughout the economy that it would be difficult to reliably collect and report 

data.23 If a job title was not accepted as a separate SOC occupation, the SOCPC then considered whether to include it in the 

Direct Match Title File, which is limited to titles that can be coded to only one SOC occupation. The job title “Sustainability 

Specialist” could belong in multiple SOC occupations, such as Environmental Engineers (17-2081), Environmental 

Engineering Technicians (17-3025), Zoologists and Wildlife Biologists (19-1023), Conservation Scientists (19-1031), or 

Forestry and Conservation Workers (45-4011). Therefore, the title “Sustainability Specialist” would not be included in the 

Direct Match Title File. In contrast, a title such as “Environmental Law Professor” can only be classified under Law 

Teachers, Postsecondary (25-1112) and would be a Direct Match Title. The SOCPC agreed to add various “green” job titles 

to the Direct Match Title File, including Environmental Economists, Hybrid Vehicle Mechanics, Environmental 

Communications Specialists, Wind Turbine Erectors, and Wind Turbine Mechanics.24

Overview of ISCO 

Work on the 2010 SOC coincided with the International Labor Organization’s revision of its 1988 International Standard 

Classification of Occupations (ISCO) for the year 2008. Like the SOC, the ISCO is a hierarchal system with major groups, 

sub-major groups, minor groups, and unit 

groups. Although the ISCO classification 

scheme is task based, eight of the ten major 

groups are also linked to one of the four 

ISCO skill levels, a divergence from the 

SOC organizing principle. These skill levels 

relate to the International Standard 

Classification of Education (ISCED) and 

roughly correspond to (1) primary, (2) 

secondary, (3) university or tertiary, and (4) 

graduate levels of education.25 Table 3 lists 

the ISCO major groups and the skill level 

for each group. The concept of skill level 

was not applied in the case of major group 

1, Managers, and major group 0, Armed 

forces occupations. 

Table 3: ISCO Major Groups with skill levels 

Major Groups ISCO Skill Level 

1 Managers 

2 Professionals 4 

3 Technicians and associate professionals 3 

4 Clerical support workers 2 

5 Service and sales workers 2 

6 Skilled agricultural, forestry, and fishery workers 2 

7 Craft and related trades workers 2 

8 Plant and machine operators, and assemblers 2 

9 Elementary occupations 1 

0 Armed forces occupations 

Another significant difference between the two classification systems is that ISCO places some emphasis on classifying 

workers in the informal economy, including work done by family members around the house. Both ISCO-88 and ISCO-08 

included categories for workers who perform subsistence agriculture and fishery workers. For example, ISCO-08 includes 

 

1919U.S. Department of Energy, Solar Energy Technologies Program, “Multi Year Program Plan, 2008-2012,” on the Internet at 

http://www1.eere.energy.gov/solar/pdfs/solar_program_mypp_2008-2012.pdf (visited Jan. 4, 2010).

20American Wind Energy Association, Oct. 20, 2009 press release, “U.S. Wind Energy Industry Installs over 1,600 MW in Third Quarter,” on the Internet at 

http://www.awea.org/newsroom/releases/10-20-09_AWEA_Q3_market_report.html (visited Jan. 4, 2010).

21See Phillip Bastian, “On the grid: Careers in Energy,” on the Internet at http://www.bls.gov/ooq/2008/fall/art02.pdf (visited Jan. 4, 2010).

22Federal Register, May 16, 2006, p. 28537.

23See Standard Occupational Classification Policy Committee, “Responses to comment on 2010 SOC,” on the Internet at 

http://www.bls.gov/soc/2010_responses/response_08-0492_08-0762_08-1157.htm (visited Jan. 4, 2010).

24See Standard Occupational Classification Policy Committee, “Responses to comment on 2010 SOC,” on the Internet at 

http://www.bls.gov/soc/2010_responses/response_08-0492_08-0762_08-1157.htm (visited Jan. 4, 2010).

25International Labour Organization, Technical Expert Group for Updating ISCO, Annex 1, “International Standard Classification of Occupations (ISCO-08) 

– Conceptual Framework,” pp. 5-6, on the Internet at http://www.ilo.org/public/english/bureau/stat/isco/docs/annex1.doc (visited Jan. 4, 2010).
 

Subsistence crop farmers (6310), Subsistence livestock farmers (6320), Subsistence mixed crop and livestock farmers (6330), 

and Subsistence fishers, hunters, trappers and gatherers (6340). A new unit occupation was added to ISCO-08 for Water and 

firewood collectors (9624), which includes work performed for subsistence, or for economic profit.26 Conversely, the first 

classification principle of the SOC limits coverage to work that is performed for pay or profit. 

 

27

Updating ISCO 

While both the ISCO and SOC revision committees indicated their intention to keep the underlying organizing principles and 

structure of the respective classification systems, significant changes were made in some areas in response to changes in 

technology. For example, both the ISCO-08 and 2010 SOC revisions aimed to accurately capture rapid changes to the 

occupational structure of the information technology sector, resulting in an increase in the number of detailed occupations, 

updated descriptions, and structural changes to this sector. Not only do these revisions more accurately describe the current 

world of work, but they also improve comparability between the two classification systems. The number of detailed 

computer occupations in the 1988 ISCO and the 2000 SOC were 4 and 10, respectively. In the revised versions of both 

classification systems, the number of computer occupations increased to 13. See appendix C for a list of the computer 

occupations included in ISCO-88, 2000 SOC, ISCO-08, and 2010 SOC. 

The robustness of the information technology sector, in terms of both industry and occupational classification, was 

recognized by Scopp, who noted that for Census, “the major occupation group with the largest percent increase from 1990 to 

2000 was the one for ‘Computer specialists,’ which more than doubled from 1990 to 2000 (122.2 percent increase). Within 

this group several detailed categories showed huge increases, some over 1000 percent: ‘Database administrators’ 

(1773.4 percent increase); ‘Computer support specialists’ (1174.9 percent); ‘Network systems and data communications 

analysts’ (1022.6 percent); ‘Network and computer systems administrators’ (514.8 percent); and ‘Computer software 

engineers’ (194.5 percent), among others.”28 Therefore, it was to be expected that the revision committees for both the ISCO 

and the SOC would carefully review the computer occupations and consider expanding the number of detailed computer 

occupations to better describe the work performed in this critical sector–with the added benefit of greatly enhancing 

comparability between the ISCO-08 and the 2010 SOC. 

Supervisors 

Another noteworthy change made to ISCO-88 relates to the treatment of supervisors within the classification structure. The

previous version, ISCO-68, had separate categories for supervisors, but ISCO-88 did not retain these, since supervisors often 

carry out the tasks and duties of the jobs they supervise, in addition to controlling the professional or technical quality of the 

work done by others. The intention was to have supervisors classified with the workers that they supervise, however since in 

many countries supervisors have the authority to hire and fire workers, some countries did not wish to include supervisors 

with the specific workers they hire and fire. Therefore, the lack of supervisors as a separate category had the potential to 

overstate the number of managers. This concern was remedied in ISCO-08. The new categories for supervisors in ISCO-08 

are: Mining supervisors (3121), Manufacturing supervisors (3122), Construction supervisors (3123), Office supervisors 

(3341), Building and housekeeping supervisors (515), and Shop supervisors (5222).29

The 2000 and the 2010 SOC both have separate categories for “Managers” and “First-line supervisors.” The language used 

in the SOC definitions for managers and in classification principle 3 specifies that these workers are engaged in planning and 

directing activities, whereas workers whose “primary duty is supervising are classified in the appropriate first-line supervisor 

category because their work activities are distinct from those of the workers they supervise.”30 Some of the most substantial 

differences between ISCO-88 and the 2000 SOC related to the treatment of supervisors. These changes to ISCO-08 will not

only allow ISCO to better reflect the workforce, they will also increase comparability between ISCO and the SOC. 

 

26International Labour Organization, Tripartite Meeting of Experts on Labour Statistics on Updating the International Standard Classification of Occupations 

(ISCO), “Resolution Concerning Updating the International Standard Classification of Occupations,” p. 34, on the Internet at 

http://www.ilo.org/public/english/bureau/stat/isco/docs/resol08.pdf (visited Jan. 4, 2010).

27 Federal Register, p. 3924, January 21, 2009.

28See Thomas Scopp, “The Relationship Between the 1990 Census and Census 2000 Industry and Occupation Classification Systems, Technical Paper #65,” 

pp. 16-17, on the Internet at http://www.census.gov/hhes/www/ioindex/pdfio/tech_0203.pdf (visited Jan. 4, 2010).

29International Labour Organization, Tripartite Meeting of Experts on Labour Statistics on Updating the International Standard Classification of Occupations 

(ISCO), “Resolution Concerning Updating the International Standard Classification of Occupations,” on the Internet at 

http://www.ilo.org/public/english/bureau/stat/isco/docs/resol08.pdf (visited Jan. 4, 2010).

30Federal Register, p. 3924, January 21, 2009.
 

Summary 

Classification systems must evolve in order to facilitate the collection of meaningful data and information. The unified 

classification structure produced by the 2010 SOC Revision process provides the foundation for future collection of the 

occupational statistics and information needed to accurately reflect the current workforce structure. The 2010 SOC reflects 

the desire of the SOCPC to retain time-series continuity, while also updating the classification to better reflect the current 

occupational structure in the U.S. economy, taking into account improvements in technology and changes to the world of 

work. Updating the occupational classification scheme will increase accuracy in collecting and reporting occupational data 

and clarifications of the definitions will ensure agreement among interpreters of the data. Only a flexible strategy for 

organizing knowledge, such as the one used to develop the SOC, can answer the challenge to maintain currency and adapt to 

unforeseen economic, social, and technological advancements. 
 

References 

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Service, October 2000. 

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on 2010 SOC,” on the Internet at http://www.bls.gov/soc/2010_responses/ (visited Jan. 4, 2010). 

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Systems, Technical Paper #65,” on the Internet at http://www.census.gov/hhes/www/ioindex/pdfio/tech_0203.pdf (visited 

Jan. 4, 2010). 

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Activities 2008,” on the Internet at http://www.eia.doe.gov/cneaf/solar.renewables/page/solarreport/solarpv.pdf (visited Jan. 

4, 2010). 
 

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Appendix A: Complete list of SOC Classification Principles and Coding Guidelines 

Classification Principles: The SOC Classification Principles form the basis on which the SOC system is structured. 

1. The SOC covers all occupations in which work is performed for pay or profit, including work performed in familyoperated enterprises by family members who are not directly compensated. It excludes occupations unique to volunteers. 

Each occupation is assigned to only one occupational category at the lowest level of the classification. 

2. Occupations are classified based on work performed and, in some cases, on the skills, education, and/or training needed 

to perform the work at a competent level. 

3. Workers primarily engaged in planning and directing are classified in management occupations in Major Group 11-0000. 

Duties of these workers may include supervision. 

4. Supervisors of workers in Major Groups 13-0000 through 29-0000 usually have work experience and perform activities 

similar to those of the workers they supervise, and therefore are classified with the workers they supervise. 

5. Workers in Major Group 31-0000 Healthcare Support Occupations assist and are usually supervised by workers in Major 

Group 29-0000 Healthcare Practitioners and Technical Occupations. Therefore, there are no first-line supervisor 

occupations in Major Group 31-0000. 

6. Workers in Major Groups 33-0000 through 53-0000 whose primary duty is supervising are classified in the appropriate 

first-line supervisor category because their work activities are distinct from those of the workers they supervise. 

7. Apprentices and trainees are classified with the occupations for which they are being trained, while helpers and aides are 

classified separately because they are not in training for the occupation they are helping. 

8. If an occupation is not included as a distinct detailed occupation in the structure, it is classified in an appropriate “All 

Other,” or residual, occupation. “All Other” occupations are placed in the structure when it is determined that the 

detailed occupations comprising a broad occupation group do not account for all of the workers in the group. These 

occupations appear as the last occupation in the group with a code ending in “9” and are identified in their title by having 

“All Other” appear at the end. 

9. The U.S. Bureau of Labor Statistics and the U.S. Census Bureau are charged with collecting and reporting data on total 

U.S. employment across the full spectrum of SOC major groups. Thus, for a detailed occupation to be included in the 

SOC, either the Bureau of Labor Statistics or the Census Bureau must be able to collect and report data on that 

occupation. 

Coding Guidelines: The SOC Coding Guidelines are intended to assist users in consistently assigning SOC codes and titles 

to survey responses and in other coding activities. 

1. A worker should be assigned to an SOC occupation code based on work performed. 

2. When workers in a single job could be coded in more than one occupation, they should be coded in the occupation that 

requires the highest level of skill. If there is no measurable difference in skill requirements, workers should be coded in 

the occupation in which they spend the most time. Workers whose job is to teach at different levels (e.g., elementary, 

middle, or secondary) should be coded in the occupation corresponding to the highest educational level they teach. 

3. Data collection and reporting agencies should assign workers to the most detailed occupation possible. Different 

agencies may use different levels of aggregation, depending on their ability to collect data. For more information on data 

produced using the SOC, see the Frequently Asked Questions (FAQs) section. 

4. Workers who perform activities not described in any distinct detailed occupation in the SOC structure should be coded in 

an appropriate “All Other” or residual occupation. These residual occupational categories appear as the last occupation 

in a group with a code ending in “9” and are identified by having the words “All Other” appear at the end of the title. 

5. Workers in Major Groups 33-0000 through 53-0000 who spend 80 percent or more of their time performing supervisory 

activities are coded in the appropriate first-line supervisor category in the SOC. In these same Major Groups (33-0000 

through 53-0000), persons with supervisory duties who spend less than 80 percent of their time supervising are coded 

with the workers they supervise. 

6. Licensed and non-licensed workers performing the same work should be coded together in the same detailed occupation, 

except where specified otherwise in the SOC definition. 
 

Appendix B: Occupations with Content Changes 

There were 60 instances of revisions to definitions that affected occupational coverage. These 60 detailed occupations are 

listed below and include the 24 new occupations denoted by an asterisk (*). 

2010 

Code 2010 SOC Title 

2010 

Code 2010 SOC Title 

11-9013 Farmers, Ranchers, and Other Agricultural Managers 29-2034 Radiologic Technologists 

11-9061 Funeral Service Managers 29-2035 Magnetic Resonance Imaging Technologists * 

13-1041 Compliance Officers 29-2057 Ophthalmic Medical Technicians * 

13-1071 Human Resources Specialists 29-2092 Hearing Aid Specialists * 

13-1075 Labor Relations Specialists 29-2099 Health Technologists and Technicians, All Other 

13-1121 Meeting, Convention, and Event Planners 29-9092 Genetic Counselors * 

13-1131 Fundraisers * 29-9099 

Healthcare Practitioners and Technical Workers, All 

Other 

13-1161 Market Research Analysts and Marketing Specialists 31-1014 Nursing Assistants 

13-1199 Business Operations Specialists, All Other 31-1015 Orderlies * 

15-1121 Computer Systems Analysts 31-9097 Phlebotomists * 

15-1122 Information Security Analysts * 31-9099 Healthcare Support Workers, All Other 

15-1134 Web Developers* 33-9032 Security Guards 

15-1142 Network and Computer Systems Administrators 33-9093 Transportation Security Screeners * 

15-1143 Computer Network Architects * 33-9099 Protective Service Workers, All Other 

15-1152 Computer Network Support Specialists * 39-4031 Morticians, Undertakers, and Funeral Directors* 

21-1091 Health Educators 41-9099 Sales and Related Workers, All Other 

21-1094 Community Health Workers * 43-3099 Financial Clerks, All Other * 

21-1099 Community and Social Service Specialists, All Other 43-9199 

Office and Administrative Support Workers, All 

Other 

23-1012 Judicial Law Clerks 47-2111 Electricians 

23-2011 Paralegals and Legal Assistants 47-2181 Roofers 

25-2051 Special Education Teachers, Preschool * 47-2231 Solar Photovoltaic Installers* 

25-2052 

Special Education Teachers, Kindergarten and 

Elementary School 47-4099 Construction and Related Workers, All Other 

25-2059 Special Education Teachers, All Other * 49-9021 

Heating, Air Conditioning, and Refrigeration 

Mechanics and Installers 

25-3099 Teachers and Instructors, All Other 49-9081 Wind Turbine Service Technicians* 

29-1128 Exercise Physiologists * 49-9099 

Installation, Maintenance, and Repair Workers, All 

Other 

29-1129 Therapists, All Other 51-3099 Food Processing Workers, All Other * 

29-1141 Registered Nurses 51-5112 Printing Press Operators 

29-1151 Nurse Anesthetists* 51-5113 Print Binding and Finishing Workers 

29-1161 Nurse Midwives * 51-9151 

Photographic Process Workers and Processing 

Machine Operators 

29-1171 Nurse Practitioners * 51-9199 Production Workers, All Other 
 

Appendix C: Computer Occupations (ISCO-88, SOC-2000, ISCO-08, SOC-2010) 

ISCO-88 

2131 Computer Systems Designers and Analysts 

2132 Computer Programmers 

2139 Computing Professionals Not Elsewhere Classified 

3121 Computer Assistants 

SOC- 2000 

15-1011 Computer and Information Scientists, Research 

15-1021 Computer Programmers 

15-1031 Computer Software Engineers, Applications 

15-1032 Computer Software Engineers, Systems Software 

15-1041 Computer Support Specialists 

15-1051 Computer Systems Analysts 

15-1061 Database Administrators 

15-1071 Network and Computer Systems Administrators 

15-1081 Network Systems and Data Communications Analysts 

15-1099 Computer Specialists, All Other 

ISCO- 08 

2511 Systems analysts 

2512 Software developers 

2513 Web and multimedia developers 

2514 Applications programmers 

2519 Software and applications developers and analysts not elsewhere classified 

2521 Database designers and administrators 

2522 Systems administrators 

2523 Computer network professionals 

2529 Database and network professionals not elsewhere classified 

3511 Information and communications technology operations technicians 

3512 Information and communications technology user support technicians 

3513 Computer network and systems technicians 

3514 Web technicians 

SOC- 2010 

15-1111 Computer and Information Research Scientists 

15-1121 Computer Systems Analysts 

15-1122 Information Security Analysts 

15-1131 Computer Programmers 

15-1132 Software Developers, Applications 

15-1133 Software Developers, Systems Software 

15-1134 Web Developers 

15-1141 Database Administrators 

15-1142 Network and Computer Systems Administrators 

15-1143 Computer Network Architects 

15-1151 Computer User Support Specialists 

15-1152 Computer Network Support Specialists 

15-1199 Computer Occupations, All Other