The U.S. Census Bureau’s County and ZIP Code Business Patterns (CBP and ZBP) datasets are generated annually from the Business Register, a large administrative database updated by several federal agencies which contains every business establishment in the U.S. with paid employees. Business establishments are defined as single physical locations where business is conducted or where services or industrial operations are performed. Establishments are assigned to industries, which are groups of businesses that produce similar products or provide similar services, using the NAICS. The ZBP contains tables with total establishments, employment, and wages by ZIP and counts of business establishments by NAICS and ZIP. The CBP has these tables plus a few others for counties.
Prior to the release of the 2017 ZBP, the number of establishments was not considered sensitive information. Therefore, counts of establishments were released without any disclosure avoidance methods applied (i.e., the data were not fudged to protect privacy). Now, however, areas with fewer than 3 establishments have been omitted.
So, what does this mean? First, for any county or ZIP Code that has fewer than 3 business establishments in total, records for that county or ZIP Code will not appear in the dataset at all (although establishments in these areas will be counted in summaries of larger areas, like states or metro areas).
Second, for a given geographic area, if a given NAICS category has less than three business establishments, the number of establishments won’t be reported for that category, but they will be included in the sum total.