Standard Industrial Classification (SIC) codes are 4-digit codes assigned by the U.S. government to identify the primary business of each establishment. 

The North American Industry Classification System (NAICS) is used by businesses and governments in the United States, Canada, and Mexico to classify all individual business locations by industry. 

The NAICS Code was developed to improve the inconsistent logic used in the SIC system and to increase specificity from the 4-digit SIC system by creating a 6-digit NAICS code.