NAICS (pronounced Nakes) was developed by the Office of Management and Budget (OMB) as the standard for use by Federal statistical agencies in classifying business establishments for the collection, tabulation, presentation, and analysis of statistical data describing the U.S. economy. Use of the standard provides uniformity and comparability in the presentation of statistics. Replaced the SIC system in 1997.
SIC is a four-digit classification system developed in the 1930's for use by the U.S. federal government. Although still used in some databases, the SIC classification system is no longer being revised.