Industry Classification Systems Used By QCEW
Employment and wage data developed in the QCEW program have been classified by industry since 1938. An
industrial code, based on a description provided by the employer on a questionnaire, is assigned to each
establishment by the State workforce agency. If a private or government employer conducts different activities
at various establishments or installations, separate industrial codes are assigned, to the extent possible, to each establishment.
The QCEW program has an extensive database of historical and current economic data. While QCEW data are not
intended to be a time series, differences in classification systems may lead to perceived discontinuity
in QCEW data.
Versions of classification systems
Please refer to the following links for detailed description on each version of NAICS, as well as its predecessor,
the Standard Industry Classificatoin (SIC) system.
- Data from 2011 forward are classified under the NAICS 2012 system.
- Data from 2007-2010 are classified under the NAICS 2007 system.
- Data from 1990-2006 are classified under the NAICS 2002 system. (Data from 1990-2000 were
originally classified under the 1987 SIC. As a NAICS reconstruction project, the data had been reclassified under the
- Data from 1988 to 2000 are classified under the 1987 SIC system.
- Data for 1975 to 1987 are classified under the 1972 SIC system. The 1977 SIC revision introduced no significant changes.
- Data from before 1975 are coded under earlier versions of the SIC system. There are no machine readable
versions of that data available at this time.
For more information on the classification systems
For a HTML view of the supersector and sector structure of NAICS, please refer to the QCEW supersector page.
There are congruency issues in the NAICS system, where there may be only one 6-digit industry, which is more detailed,
under a 5-digit industry. The QCEW program has created an easy-to-read list of all NAICS congruencies.
Please refer to the QCEW NAICS congruencies page.
For a break-down of the SIC industries, please refer to the Occupational Safety and Health Administration
SIC manual. For more information on QCEW data classified
under SIC, please refer to the technical readme.
Last Modified Date: October 21, 2011