Industry, Occupation, and Class of Worker In the 2000-2002 ACS Public Use Microdata Samples

(Back to Occupation Coding Guidelines Index)

[Excerpted from "American Community Survey: 2002 Subject Definitions", prepared by the Bureau of the Census. Washington: The Bureau (producer and distributor), pp. 30-33.]

Industry, Occupation, and Class of Worker

The data on industry, occupation, and class of worker were derived from answers to questionnaire items 34 through 39. These questions were asked of all people over 15 years old who had worked in the past 5 years. Information on industry relates to the kind of business conducted by a person's employing organization; occupation describes the kind of work the person does on the job.

For employed people, the data refer to the person's job during the reference week. For those who worked at two or more jobs, the data refer to the job at which the person worked the greatest number of hours. For unemployed people, the data refer to their last job. The industry and occupation statistics are derived from the detailed classification systems developed for the 2000 census as described below. Respondents provided the data for the tabulations by writing on the questionnaires descriptions of their industry and occupation. Those cases were sent to an automated coder (computer software). These descriptions were keyed. A clerical staff in the National Processing Center in Jeffersonville converted the written questionnaire descriptions to codes by comparing these descriptions to entries in the Alphabetical Index of Industries and Occupations. For the industry code, these coders also referred to an Employer Name List (formerly called Company Name List). This list, prepared from the American Business Index (ABI), contained the names of business establishments and their North American Industrial Classification System (NAICS) codes converted to population census equivalents. This list facilitated coding and maintained industrial classification comparability.


The American Community Survey uses the industry classification system developed for the 2000 census. This system consists of 265 categories for employed people, classified into 20 sectors. The 2000 census classification was developed from the 1997 NAICS published by the Executive Office of the President Office of Management and Budget.

The NAICS was designed to create a new classification system to include industries in Canada and Mexico with those of United States. However, census data, which were collected from households, differ in detail and nature from those obtained from establishment surveys. Therefore, the census classification systems, while defined in NAICS terms, cannot reflect the full detail in all categories.


The American Community Survey uses the occupational classification system developed for the 2000 census. This system consists of 509 specific occupational categories for employed people arranged into 23 major occupational groups. This classification was developed to be consistent with the Standard Occupational Classification (SOC) Manual: 2000, published by the Executive Office of the President Office of Management and Budget. Tabulations with occupation as the primary characteristic present several levels of occupational detail. The most detailed tabulations will be shown in a special 2000 subject report, CD-ROMs and on the internet. These products contain all 509 occupational categories plus industry or class of worker sub-groupings of occupational categories.

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 profession include occupations such as janitor, security guard, and secretary.

Class of Worker

The data on class of worker was derived from answers to questionnaire item 34. The information on class of worker refers to the same job as a respondent's industry and occupation and categorizes people according to the type of ownership of the employing organization. The class of worker categories are defined as follows:

Private Wage and Salary Workers -- Includes people who worked for wages, salary, commission, tips, pay-in-kind, or piece rates for a private for profit employer or a private not-for-profit, tax-exempt or charitable organization. Self-employed people whose business was incorporated are included with private wage and salary workers because they are paid employees of their own companies. Some tabulations present data separately for these subcategories: "For profit," "Not for profit," and "Own business incorporated."

Government Workers -- Includes people who were employees of any local, State, or Federal governmental unit, regardless of the activity of the particular agency. For some tabulations, the data were presented separately for the three levels of government.

Employees of foreign governments, the United Nations, or other formal international organizations controlled by governments should be classified as "Federal Government employee."

Self-Employed in own not Incorporated Business Workers -- Includes people who worked for profit or fees in their own unincorporated business, profession, or trade, or who operated a farm.

Unpaid Family Workers -- Includes people who worked 15 hours or more without pay in a business or on a farm operated by a relative.

Salaried/Self-Employed -- In tabulations that categorize people as either salaried or self-employed, the salaried category includes private and government wage and salary workers; self-employed includes self-employed people and unpaid family workers.

The industry category, "Public administration," is limited to regular government functions such as legislative, judicial, administrative, and regulatory activities of governments. Other government organizations such as schools, hospitals, liquor stores, and bus lines are classified by industry according to the activity in which they are engaged. On the other hand, the class of worker government categories includes all government workers.

Occasionally respondents supplied industry, occupation, or class of worker descriptions that were not sufficiently specific for precise classification or did not report on these items at all. In the coding operation, certain types of incomplete entries were corrected using the Alphabetical Index of Industries and Occupations. For example, it was possible in certain situations to assign an industry code based on the occupation reported, or vice versa.

Following the coding operations, there was a computer edit and an allocation process. The edit first determined whether a respondent was in the universe that required an industry and occupation code. The codes for the three items (industry, occupation, and class of worker) were checked to ensure they were valid and were edited for their relation to each other. Invalid and inconsistent codes were either blanked or changed to consistent code.

If one or more of the three codes was blank after the edit, a code was assigned from a "similar" person based on other items such as age, sex, education, and weeks worked. If all of the labor force and income data were blank, all of these economic items were assigned from one other person who provided all the necessary data.


Comparability for data for the 1998 and 1999 ACS primarily used the same classification systems used for the1990 Census. For the 1999 and 2000 ACS the data was made comparable to the Census 2000 because of changes to the industrial and occupation classification systems. Changes in the nature of jobs and respondent terminology, and refinement of category composition made it necessary for comparability of data. In ACS as in Census 2000, both the industry and occupation classifications had major revisions to reflect changes to the North American Industrial Classification System (NAICS) and the Standard Occupational Classification (SOC). The conversion of these classifications means that the 2000 classification systems are less comparable to the classifications used in earlier surveys.

There is a small difference in the 'Class of Worker' question on the 1996-1998 American Community Survey questionnaire from the 1999-2001 American Community Survey, and the 1990 and 2000 decennial census questionnaires. The 1996-1998 American Community Survey has an additional response category for 'Active duty US Armed Forces'. People who marked this category are tabulated as Federal government workers. Otherwise, the questions and classification systems are the same as the 1990 and the 2000 decennial census.

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