How are individual businesses classified?
The economic census classifies each business establishment by geography and industry. We don't, as a rule, assign geographic or industry classifications to multi-establishment firms. The industry classifications for all establishments covered by the economic census and surveys are based on the North American Industry Classification System (NAICS).
The method of assigning industry classifications is described in the Methodology section of the 2007 Economic Census User Guide.
For more information on NAICS and industry classification in general, see the section on Business Classification.