Industries: Classification

•  NAICS - North American Industry Classification System (Reference HF1042 .N67 2007)
  Available in print and also free on the Internet, the North American Industry Classification System is the current hierarchal classification system of industry developed jointly by Canadian, Mexican, and U.S. government agencies.  Identifying an industry’s NAICS number can facilitate business research.  A NAICS number can be two to six digits long.  The first two digits designate the sector, the third digit represents the subsector, the fourth digit designates the industry group, the fifth digit represents the NAICS industry, and the sixth digit designates the national industry (See example below).  NAICS replaces the Standard Industrial Classification (SIC) system. 

• SIC - Standard Industrial Classification (Reference HF1042 .U5 1987)  
  The predecessor to NAICS, the Standard Industrial Classification system is still used by many business information sources (e.g., Encyclopedia of American Industries).  SIC numbers are 2 to 4 digits long.  The longer the number, the more specific the industry.  Be aware that the companies Dun & Bradstreet and InfoUSA have created their own proprietary extended SIC numbers that can be up to 8-digits long, which are useful for niche industry research. 

Other Classification Systems

• North American Product Classification System (NAPCS)
  Joint product classification project of governmental statistical agencies of Canada, Mexico, and the United States.  In process. 
  
  
• Harmonized Tariff Schedule of the United States
  Product classification system for imports.

• Available Classifications
  The United Nations collection of classification systems.