Occupation describes the kind of work a person does on the job. Occupation data were derived from answers to questions 45 and 46 in the 2013 American Community Survey. Question 45 asks: "What kind of work was this person doing?" Question 46 asks: "What were this person's most important activities or duties?"

These questions were asked of all people 15 years old and over who had worked in the past 5 years. For employed people, the data refer to the person's job during the previous week. For those who worked two or more jobs, the data refer to the job where the person worked the greatest number of hours. For unemployed people and people who are not currently employed but report having a job within the last five years, the data refer to their last job.

These questions describe the work activity and occupational experience of the American labor force. Data are used to formulate policy and programs for employment, career development and training; to provide information on the occupational skills of the labor force in a given area to analyze career trends; and to measure compliance with antidiscrimination policies. Companies use these data to decide where to locate new plants, stores, or offices.

Coding Procedures - Occupation statistics are compiled from data that are coded based on the Standard Occupational Classification (SOC) Manual: 2021 (http://www.bls.gov/soc), published by the Executive Office of the President, Office of Management and Budget. Census occupation codes, based on the 2021 SOC, provide 569 specific occupational categories, for employed people, including military, arranged into 23 major occupational groups, plus an additional Census code for the unemployed, with no work experience in the last 5 years or earlier or never worked for a total of 570 Census occupation codes.

Respondents provided the data for the tabulations by writing on the questionnaires descriptions of the kind of work and activities they are doing. These write-ins are converted to a code category through automated coding. Cases not autocoded on both industry and occupation are sent to the clerical staff in the National Processing Center (NPC) in Jeffersonville, Indiana, who assign codes by comparing these descriptions to entries in the Alphabetical Index of Industries and Occupations (https://www.census.gov/topics/employment/industry-occupation/guidance/indexes.html).

Some occupation groups are related closely to certain industries. Operators of transportation equipment, farm operators and workers, and healthcare providers account for major portions of their respective industries of transportation, agriculture, and health care. However, the industry categories include people in other occupations. For example, people employed in agriculture include truck drivers and bookkeepers; people employed in the transportation industry include mechanics, freight handlers, and payroll clerks; and people employed in the health care industry include janitors, security guards, and secretaries.

Editing Procedures - Following the coding operation, a computer edit and allocation process excludes all responses that should not be included in the universe, and evaluates the consistency of the remaining responses. The codes for occupation are checked for consistency with the industry and class of worker data provided for that respondent. Occasionally respondents supply occupation descriptions that are not sufficiently specific for precise classification, or they do not report on these questions at all. Certain types of incomplete entries are corrected using the Alphabetical Index of Industries and Occupations. If one or more of the three codes (occupation, industry, or class of worker) is blank after the edit, a code is assigned from a donor respondent who is a "similar" person based on questions such as age, sex, educational attainment, income, employment status, and weeks worked. If all of the labor force and income data are blank, all of these economic questions are assigned from a "similar" person who had provided all the necessary data.

Question/Concept History - OOccupation data have been collected during decennial censuses since 1850. Starting with the 2010 Census, occupation data was no longer collected during the decennial census. Long form data collection has transitioned to the ACS. The ACS began collecting data on occupation in 1996. The questions on occupation were designed to be consistent with the 1990 Census questions on occupation. ACS questions on occupation have remained consistent between 1996 and 2021.

Limitation of the Data - Beginning in 2006, the population in group quarters (GQ) was included in the ACS. Some types of GQ populations have occupational distributions that are different from the household population. The inclusion of the GQ population could therefore have a noticeable impact on the occupational distribution in some geographic areas with a substantial GQ population.

Data on occupation, industry, and class of worker are collected for the respondent's current primary job or the most recent job for those who are not employed but have worked in the last 5 years. Other labor force questions, such as questions on earnings or work hours, may have different reference periods and may not limit the response to the primary job. Although the prevalence of multiple jobs is low, data on some labor force items may not exactly correspond to the reported occupation, industry, or class of worker of a respondent.

Comparability - Comparability of occupation data was affected by a number of factors, primarily the system used to classify the questionnaire responses. Changes in the occupational classification system limit comparability of the data from one year to another. These changes are needed to recognize the "birth" of new occupations, the "death" of others, the growth and decline in existing occupations, and the desire of analysts and other users for more detail in the presentation of the data. Probably the greatest cause of noncomparability is the movement of a segment from one category to another. Changes in the nature of jobs, respondent terminology, and refinement of category composition made these movements necessary.

ACS data from 1996 to 1999 used the same occupation classification systems used for the 1990 Census; therefore, the data are comparable. Since 1990, the occupation classification has been revised to reflect changes within the Standard Occupational Classification (SOC). The SOC was updated in 2000 and these changes were reflected in the Census 2000 occupation codes. For more information on occupational comparability across classification systems, please see technical paper #65: The Relationship Between the 1990 Census and Census 2000 Industry and Occupation Classification Systems (https://www.census.gov/content/dam/Census/library/workingpapers/2003/demo/techpaper2000.pdf). The 2000-2002 ACS data used the same occupation classification systems used for Census 2000; therefore, the data are comparable. Because of the possibility of new occupations being added to the list of codes, the Census Bureau needed to have more flexibility in adding codes. Consequently, in 2002, Census occupation codes were expanded from three-digit codes to four-digit codes. For occupation, this entailed adding a "0" to the end of each occupation code. The SOC was revised once more in 2010. Based on the 2010 SOC changes, Census codes were revised resulting in a net gain of 30 Census occupation codes (from 510 occupations to 540 occupations). Most of these changes were concentrated in information technology, healthcare, printing, and human resources occupations. The SOC was revised once again in 2021. Based on the 2021 SOC changes, the Census codes were revised resulting in a net gain of 30 Census occupation codes (from 540 occupations to 570 occupations). The 2021 Census occupation codes were first applied to the 2021 ACS. The 2021 Census occupation codes changes These substantive changes across multiple occupation groups make the 2021 Census occupation codes non-comparable with previous years without the use of the occupation crosswalk and conversion rates. For information on the 2021 SOC and Census occupation codes, please see the 2021 Census Occupation Codes with Crosswalk document, which includes the summary of 2021 changes and the Census 2010 to 2021 occupation codes crosswalk on the Industry and Occupation Code Lists & Crosswalks page (https://www.census.gov/topics/employment/industryoccupation/guidance/code-lists.html).

For more information, see the Census Occupation Code List found within the 2021 ACS Code List. Go to https://data.census.gov. and enter "ACS Code Lists, Definitions, and Accuracy" in the search box.

See also, Industry and Class of Worker.