Why don the NAICS categories within a sector add to sector totals?
• The first thing is to understand what is supposed to add up. Theoretically, any sector (2-digit NAICS) total should equal the sum of component subsectors (3-digit NAICS), each 3-digit figure should correspond to the sum of component 4-digits, and so forth. If you add together NAICS codes at more than one level, you could get a sum greater than the true total. • At the same time, below the national level, NAICS categories are published only when they meet certain criteria that vary from industry to industry. For example, county or city figures are shown only for those manufacturing industry categories that have at least 500 employees. Your detailed figures may not add to higher level totals because some categories simply aren’t shown. (For missing industries, you may check County Business Patterns, which does not have publication cutoffs. The first year CBP used NAICS was 1998.) • Some figures are withheld (replaced with D) to avoid disclosure of confidential information. Data withhel
