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Industry Classification Systems

It is often necessary to identify the proper numeric classification code when researching an industry. To find the corresponding codes, use the following sources:


Standard Industrial Classification Manual (SIC) (1987= latest edition)
DOCS REF HF 1042 .A55 or DOCS-REF HF 1042 .U622 [On Business Index Table]

The four-digit Standard Industrial Classification Code is used to gather and analyze information on U.S. businesses. The first two digits describe the general industry. The third and fourth digits describe the specific activity. Users should note that effective with the 1997 Economic Census, the SIC has been replaced by the North American Industrial Classification.


Name Classification Level
D Manufacturing Division (Letter designation)
20 Food and Kindred Products Major Group
205 Bakery Products Industry Group
2052 Cookies and Crackers Industry



Search SIC on the Web:


NAICS Structure

NAICS uses a six-digit coding system to identify particular industries and their placement in this hierarchical structure of the classification system. The first two digits of code designate the sector, the third designates the subsector, the fourth digit designates the industry group, the fifth digit designates the NAICS industry, and sixth digit designates the U.S. detail industry. For example


Name Classification Level
31-33 Manufacturing Sector
316 Leather and Allied Product Manufacturing Subsector
3162 Footwear Manufacturing Industry Group
31621 Footwear Manufacturing Industry
316211 Rubber and Plastics Footwear Manufacturing
(e.g. Athletic shoes, plastics/rubber or plastics/rubber
soled fabric upper manufacturing)
U.S. Detail Industry


Where Do You Find NAICS?

  • North American Industry Classification System (NAICS)
    DOCS REF HF 1041.5 .N674 1997 [On Business Index Table]

Users should note that effective with the 1997 Economic Census, the NACIS is replacing the SIC system. However, it has not yet come into wide use among commercial providers of business data. Consult the U.S. Bureau of Census NAICS site for a list of NAICS codes, tables showing correspondence between NAICS and the SIC system, and other information on how NAICS differs from the SIC System.


Search NAICS on the Web

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Created by kzhang on Jun 18, 2012 Last updated Aug 2, 2012
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