Background on the Data

Sidebar to: The Changing Employment Landscape

Beginning with January 2003 reporting for states and areas and May 2003 reporting for the nation, (1) the CES program switched to the North American Industry Classification System (NAICS), thus ending a long tradition of using Standard Industrial Classification (SIC). (2) Although it is generally agreed that NAICS is a great improvement over the obsolete SIC, the change created a break in the time series — something we research analyst types dislike very much. The BLS has since converted SIC data to NAICS, and all NAICS series have been reconstructed back to at least 1990. (3) Some NAICS series have been extended all the way back to 1939. Others go back to some year in between, depending on the characteristics of the original data.

There is no perfectly clean bridge from SIC to NAICS (nor from NAICS to SIC). (4) The reconstructed data have limitations. However, for this article, I focus primarily on the simple dichotomy between goods-producing and service-providing employment (5); and my confidence in the reconstructed data for this purpose is pretty high.


  1. See for a helpful excerpt from Monthly Labor Review Online, and links to related articles.
  2. For more details about the switch from SIC to NAICS, read the IN Context series of articles at, and also visit the U.S. Bureau of Labor Statistics website:
  3. The conversion ratios are available at
  4. See for links to the various correspondence tables.
  5. For a listing of the NAICS sectors and BLS supersectors that comprise goods-producing and service-providing employment, see