Chapter 3.
Occupational Employment Statistics

Concepts
An establishment is an economic unit which processes goods or provides services, such as a factory, mine, or store. It is generally at a single physical location and is engaged primarily in one type of economic activity. Single physical locations that encompass two or more distinct economic activities are treated as two or more establishments, provided that separate payroll records are available and certain other criteria are met.

Unit total employment is the number of workers who can be classified as full time or part time, workers on paid vacations or other types of leave, workers on unpaid or short-term absences (i.e., illness, bad weather, temporary layoff, jury duty), salaried officers, executives, staff members of incorporated firms, employees temporarily assigned to other units, and employees for whom this unit is their permanent (home) duty station regardless of whether this unit prepares their paycheck. Unit total employment excludes proprietors (owners and partners) of unincorporated firms, unpaid family workers, workers on extended leave (i.e., pensioners and members of the Armed Forces), and workers on long-term layoff.

Employees are reported in the occupation in which they are working, even if they have been trained for a different occupation. For example, an employee trained as an engineer but working as a drafter is reported as a drafter.

Working supervisors, those spending 20 percent or more of their time at work similar to that performed by workers under their supervision, are reported in the occupations which are most closely related to their work.

Part-time workers, learners, and apprentices are reported in the occupation in which they ordinarily work.

Industrial classification
The industrial classification system currently used for compiling and publishing OES survey data is defined in the 1987 Standard Industrial Classification Manual. (See appendix B in the print edition of the BLS Handbook of Methods for a detailed description of this system.)

Under the Standard Industrial Classification (SIC) system, reporting establishments are classified on the basis of major product or activity.

Occupational classification
The OES classification system emphasizes occupations of special interest to many data users, such as technology-related occupations and those which require substantial training. In addition, the system is concise and compatible with the 1980 Standard Occupational Classification (SOC) system. The titles and descriptions of occupations are principally derived from the Dictionary of Occupational Titles (DOT). The classification of occupations, with some exceptions, follows the SOC principles which group occupations by function, industry, and skill.

A "crosswalk," which relates OES occupations to the SOC, the 1990 census classification system, and the DOT, has been developed so that users can use OES data in conjunction with these other sources. With crosswalks, each classification system can be used as a common denominator.

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