Industry data describe the kind of business conducted by a person's employing organization. These data are derived from a combination of write-in and check box questions, which are autocoded and clerically coded by Census Bureau staff, using the Census Industry Code List developed for Census Bureau household surveys. Beginning in 2018, this system consists of 270 categories for employed people, including military, classified into 20 sectors.

The primary sources of household industry data are currently the American Community Survey (ACS) and the Puerto Rico Community Survey (PRCS), which collect the detailed data previously covered by the decennial census long forms until 2000. The ACS has collected industry data since the first survey in 1996. For the Island Areas—the United States Virgin Islands (USVI), the Commonwealth of the Northern Mariana Islands (CNMI), Guam, and American Samoa— the Island Areas Census, which uses a form based on the ACS and modified for these areas, is still the main data source.

Industry data from business establishments are separately collected by the Census Bureau through the Economic Programs Directorate.

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, and to measure compliance with antidiscrimination policies. Mandated reports for Congress on the labor force rely on the analysis of these characteristics. Further, the Bureau of Economic Analysis uses this information, in conjunction with other data, to develop its state per capita income estimates used in the allocation formulas or for eligibility criteria in many federal programs such as Medicaid, and plans to use the county-level information to develop its county and state per capita income estimates.

Information about industry is also important for creating jobs as companies use these data to decide where to locate new plants, stores, or offices. Agencies use these data to plan job training programs. Federal agencies use these data in litigation where employment discrimination is alleged. Locally, data are used to estimate the demand for staff in the healthcare industry and their geographic distribution based on these data.

On the ACS, demographic industry data are derived primarily from answers to questions 42 b, c, and d.  These questions are asked of all people 15 years old and over who had worked in the past 5 years. The text of these questions as they appear in the 2019 ACS questionnaire is as follows:

Question 42 b. What was the name of this person’s employer, business, agency, or branch of the Armed Forces?
(Write-in field)

Question 42 c. - What kind of business or industry was this?
Include the main activity, product, or service provided at the location employed. (For example: elementary school, residential construction) 
(Write-in field)

Question 42 d. - Was this mainly - (Mark (X) ONE box.)
(Boxes located to the left of each response category)

• manufacturing?

• wholesale trade?

• retail trade?

• other (agriculture, construction, service, government, etc.)?

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 in the labor force but report having had a job within the last five years, the data refer to their last job.

In the 1990 Census, and starting with the 1999 ACS, a check box was added to the employer name question to be marked by anyone "now on active duty in the Armed Forces...". This information was used by the industry and occupation coders to assist in assigning proper industry codes for active duty military. Between 1996-1998, the ACS class of worker question had an additional response category for "Active duty U.S. Armed Forces member." In 2016, ACS underwent content testing for the class of worker, industry, and occupation questions. As a result, in 2019, ACS adopted an additional response category of “Active Duty or U.S. Armed Forces or Commissioned Corps” in the Class of Worker question to aide coders in assigning the best industry code for military cases. Other changes were implemented to the formatting, numbering of questions, and write-in industry and occupation questions examples provided on the questionnaire.

The Census Bureau has maintained its own code list since 1910.  Written responses to the occupation questions are coded using the Census Industry Code list based on the 2017 North American Industry Classification System (NAICS) published by the Executive Office of the President, Office of Management and Budget (OMB).  The Census Industry Code list consists of 270 categories for employed people, including military, classified into 20 sectors. The first NAICS was developed in 1997 as an improvement over the Standard Industrial Classification (SIC) system that had been previously updated from the 1930s through 1987. The NAICS has been updated every five years – 1997, 2002, 2007, 2012, and 2017.  It was developed to increase comparability in industry definitions between the United States, Mexico, and Canada. It provides industry classifications that group establishments into industries based on the activities in which they are primarily engaged. The NAICS was created for establishment designations and provides detail about the smallest operating establishment, while data collected from households differ in detail and nature from those obtained from establishment surveys. Because of potential disclosure issues, the Census Industry Code List, while defined in NAICS terms, cannot reflect the full detail for all categories.

In addition, ACS used 3-digit census industry codes until 2002, when it transitioned to 4-digit industry codes. As the NAICS changes, the Census Bureau updates its code lists, coding procedures, and data products accordingly.

It should be noted that the industry category, "Public administration," is limited to regular government functions such as legislative, judicial, administrative, and regulatory activities. Other government organizations such as public schools, public hospitals, and bus lines are classified by industry according to the activity in which they are engaged.

For full code lists and other technical information, please see our Guidance for Data Users Page.

Occasionally respondents supply industry 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 variables (occupation, industry, or class of worker) is blank after edit procedures, 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.

Demographic 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 unemployed or out of the labor force 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 of industry data across time is affected by a number of factors, primarily the system used to classify the questionnaire responses. These changes are needed to recognize when new industries emerge, the growth and decline in existing industries, and the desire of analysts, researchers, and other users for more detail in the presentation of the data. Usually, the greatest cause of non-comparability is the movement of a segment from one sector to another. Changes in the nature of jobs, respondent terminology, and refinement of category composition made these movements necessary. These changes in the industry classification system thus limit comparability of the data from one year to another, and with other surveys that use older classification systems (see below).

Since 1990, the industry classification has had major revisions to reflect the shift from the Standard Industrial Classification (SIC) to the North American Industry Classification System (NAICS). These changes were reflected in the Census 2000 industry codes. For more information on industry comparability across classification systems, please see Technical Paper #65: The Relationship Between the 1990 Census and Census 2000 Industry and Occupation Classification Systems. The 2000-2002 ACS data used the same occupation classification systems used for the 2000 census, therefore, the data are comparable. In 2002, NAICS underwent another change and the industry codes were changed accordingly. Because of the possibility of new industries being added to the list of codes, the Census Bureau needed to have more flexibility in adding codes. Consequently, in 2002, Census Bureau industry codes were expanded from three-digit codes to four-digit codes. Also, 5 new codes were added between 1997 and 2002 (4585, 5591, 5592, 6675, 6692, and 6695). Changes between 2002 and 2007 were focused on the Information Sector where one census code was added (6672) and two were deleted (6675, 6692).

The ACS followed the 2007 code list through 2012, making the ACS 2008-2012 industry codes comparable. NAICS was updated again in 2012. The changes were used to create the 2012 Census Industry Code List, which was first applied to the 2013 ACS and used until the 2017 ACS. The revision included 9 new codes (3095, 3365, 3875, 3895, 4195, 4265, 4795, 5275, and 5295), 9 deletions (3090, 3360, 3870, 3890, 4190, 4260, 4790, 5270, and 5290) and 19 title changes. Then, between 2012 and 2017, NAICS updates resulted in 19 new Census industry codes (1691, 3291, 4971, 4972, 5381, 5391, 5593, 6991, 6992, 7071, 7181, 8191, 8192, 8561, 8562, 8563, 8564, and 8891) and 18 deleted ones (1680, 1690, 3190, 3290, 4970, 5380, 5390, 5590, 6990, 7070, 7180, 8190, 8560, 8880, and 8890). These changes were applied to the 2018 ACS, making the 2017 Census industry codes only partially comparable with previous years.