The American workforce is made up of many different types of jobs that are categorized into sectors defined by the North American Industry Classification System (NAICS; pronounced "Nakes"). Adopted in 1997, NAICS was devised by the U.S. Economic Classification Policy Committee in conjunction with Statistics Canada and the Instituto Nacional de Estadística, Geografia e Informática of Mexico, and is the standard classification system for businesses throughout the continent of North America. There are twelve major industry sectors tracked by the U.S. Department of Labor's Bureau of Labor Statistics (BLS), which are referred to as supersectors. These supersectors encompass all private and public jobs within the United States and businesses owned by U.S.-based companies operating in other countries.

The twelve supersectors are:

• Construction
• Education and Health Services
• Financial Activities
• Government
• Information
• Leisure and Hospitality
• Manufacturing
• Natural Resources and Mining
• Professional and Business Services
• Other Services
• Transportation and Utilities
• Wholesale and Retail Trade

Table 2.1, developed by the U.S. Department of Commerce, Bureau of Economic Analysis (BEA), shows annual gross output (the market value of an industry's production) by industry and category between 2000 and 2003.

Virtually every job can be placed into one of these categories. It should be noted that industry tracking focuses on the core mission of the business rather than on the particular tasks performed by employees. For instance, the service industry, as defined by the government, includes businesses whose main function is to provide a service rather than a product. This is different from the popular notion of the service industry, which includes any employment position that renders service. Waiting tables, for example, is considered part of the leisure and hospitality supersector rather than the services sector; jobs in public schools and government-owned hospitals are considered part of the government sector rather than education and health services.