The Current Population Survey (CPS or "household" survey) currently uses the 2010 Census occupational classification and the 2007 Census industry classification. These classifications were derived from the 2010 Standard Occupational Classification (SOC) and the 2007 North American Industry Classification System (NAICS), respectively.
The 2010 Census occupational classification was introduced with data for January 2011 and replaced an earlier version that was based on the 2000 SOC. As a result of the classification change, occupational data beginning with January 2011 are not strictly comparable with earlier years. Although the names of the broad- and intermediate-level occupational groups in the 2010 Census occupational classification remained the same, some detailed occupations were re-classified between the broader groups, affecting comparability over time.
At the detailed occupation level, there are numerous differences between the 2010 Census occupational classification and the earlier classification. With the introduction of the 2010 classification, 50 new detailed occupations were introduced, 20 detailed occupations were discontinued, and the scope of 18 detailed occupations was redefined (although the titles did not change), creating breaks in series comparability.
The 2007 Census industry classification was introduced with data for January 2009 and replaced an earlier version based on the 2002 NAICS. The differences between the 2007 and 2002 industry classifications were relatively minor and did not involve re-classification of industries between the broader industry sectors. Most of the changes affected the detailed industries and intermediate groups in the Information sector.
Because the Census occupational and industry classifications are adaptations of the SOC and NAICS, occupational and industry statistics from the CPS are not strictly comparable with statistics from other sources that use the SOC and NAICS directly. The following documents provide listings of the specific or "detailed" Census occupational and industry classifications and the broad or "major" groups to which they are aggregated in many data presentations. These listings include SOC and NAICS crosswalk information; that is, they show the corresponding SOC and NAICS codes for the detailed Census occupations and industries. Data users should note that there is not always a one-to-one match between the Census classifications and the SOC and NAICS.
In January 2003, the CPS adopted the 2002 Census occupational and industry classification systems; they replaced the 1990 Census occupational and industry classifications. The introduction of these classification systems created a complete break in comparability with existing data series at all levels of occupation and industry aggregation. The composition of detailed occupations and industries changed substantially in the 2002 systems compared with the 1990 systems, as did the structure for aggregating them into major groups. Hence, any comparisons of data on the different classifications are not possible without major adjustments.
For more information on the significant differences between the 1990 and 2002 classification systems, see the February 2003 article on changes introduced to the CPS in January 2003. (PDF)
Historical employment series on the 2002 Census classifications are available at broad levels of occupational and industry aggregation back to 1983. BLS constructed these historical series based on the distribution of employment re-coded from the 1990 classifications to the 2002 classifications for the years 2000-2002. Information about these reconstructed series with instructions for accessing the data is available on the BLS website at www.bls.gov/cps/constio198399.htm.
Historical employment series at the detailed occupational and industry levels on the 2002 classifications are available back to 2000 only. The data for 2000-2002 are not available on the BLS website, but can be obtained in unpublished files from the Division of Labor Force Statistics; to request these tables, email or telephone (202) 691-6378.
Industry data beginning in January 2009 use the 2007 Census industry classification system, which was derived from NAICS 2007. The differences between the 2002 and 2007 Census industry classifications are relatively insignificant. Several industry titles were revised with no change to the industry definitions. In the "Information" sector, there were some minor definitional changes to a few detailed industries. BLS did not make any revisions to historical data with the introduction of the Census 2007 industry classification.
Some researchers may need to maintain ongoing CPS employment series that are not included in the historical data described above. For these data users, BLS has created conversion factors between the 1990 and 2002 Census classifications. These factors are based on three-year average survey microdata (2000-2002) that were coded to both the old and new classification systems. They are tabulated at the major group level as well as by the detailed classifications.
The conversion factors, provided in Tables 1-8 below, show the percent distribution of employment re-coded from one classification system to another. To illustrate, Table 1 shows employment estimates for each major occupational group under the 1990 classification and the percent of employment that was re-coded into the major groups based on the 2002 classification. These percentages could be applied to historical employment data on the 1990 classification to approximate employment on the 2002 classification. The resulting series provides a general employment trend over time but—given that it is only an approximation—the data are not likely to be useful for precise point-to-point comparisons or measuring actual change over time.
Important notice to users of the conversion factors: Occupation and industry coding of CPS microdata records is carried out by the U.S. Census Bureau. Detailed occupational or industry classifications will sometimes have to be imputed or "allocated" when sufficient information to assign a classification cannot be obtained. In addition, despite best practices, some classification error will occur. The conversion factors incorporate classifications that were allocated or, on occasion, mis-assigned. As a result, users of these conversion factors may notice atypical occupations and industries appearing in the detailed distributions, but they generally represent a very small portion of employment. Users also should note that at the detailed classification level, all occupations and industries with less than 10,000 average employment are excluded from the tables. Within the distributions, percentages less than 0.05 will not be shown separately at either the detailed or major group level.
Last Modified Date: April 1, 2011