Guides
Sample Plans
The Federal government classifies manufacturing and service industries and assigns each a Standard Industrial Classification (SIC) code to promote the comparability of statistics. The SIC/NAICS codes are used in many online and print resources to classify establishments in the same industry.
The SIC code was revised over the years and some code numbers have changed reflecting changes in the American economy. Be careful when comparing data from different publishers over a long period of time. Beginning with the 1997 Economic Census, the Census Bureau began using the North American Industrial Classification System (NAICS) (pronounced "nakes") which is more closely aligned with international codes. Many commercial publications have converted to NAICS, but some still use SIC codes.