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Labor Force Statistics from the Current Population Survey
Bureau of Labor Statistics > Current Population Survey > Methods > Other technical documentation

Technical Documentation (CPS)

This page contains technical documentation and related information on the Current Population Survey (CPS).

On This Page

Concepts and methodology of the CPS

Summarized documentation on the concepts and methodology of the CPS.

  • Concepts and definitions
  • How the government measures unemployment (HTML) (PDF)
  • Understanding BLS Unemployment Statistics (Video)
  • Quick Guide to Methods and Measurement Issues in the monthly Employment Situation report (HTML)
  • Handbook of Methods (HTML) (PDF)
  • Technical notes to household survey data published in Employment and Earnings (2004)
    • Introduction (Relationship and comparability with establishment and other surveys) (PDF)
    • Collection and Coverage, Historical Comparability and Estimating Methods (PDF)
    • Seasonal adjustment (PDF)

Comprehensive documentation on the design and methodology of the CPS, including a history of the survey (links to the U.S. Census Bureau website).

  • Current Population Survey, design and methodology (Technical paper 77) (October 2019) (PDF 4.8MB)
    • Previous versions:
      • Technical paper 66, October 2006 (PDF 3.2MB)
      • Technical paper 63, revised March 2002 (PDF 3.1MB)
      • Technical paper 63, March 2000 (PDF 2.2MB)
  • Additional information about the CPS, including documentation for survey microdata, is available from the Census Bureau

Historical comparability is affected by revisions to population controls, changes in occupational and industry classification, and other changes to the survey.




CPS and CES employment differences

BLS has two monthly surveys that measure employment levels and trends:

  • the Current Population Survey (CPS), also known as the household survey
  • the Current Employment Statistics (CES) survey, also known as the payroll or establishment survey

See Comparing employment from the BLS household and payroll surveys for information on the differences in the two employment measures, as well as trend divergences that sometimes occur.




How the government measures unemployment

Description of how the national unemployment statistics are developed from the Current Population Survey (CPS), written in non-technical language.

  • How the government measures unemployment (HTML) (PDF)
  • Understanding BLS unemployment statistics (Video)



Occupational and industry classifications used in the CPS

BLS publishes both employment and unemployment data by occupation and industry from the CPS.

The occupational classification reflects the type of job or work that the person does, while the industry classification reflects the business activity of their employer or company. The occupational and industry classifications are based on a person's sole or primary job, unless otherwise specified. For the unemployed, the occupation and industry are based on the last job held.

Beginning with data for January 2020, the Current Population Survey uses the 2018 Census occupational classification and the 2017 Census industry classification. These classifications were derived from the 2018 Standard Occupational Classification (SOC) and the 2017 North American Industry Classification System (NAICS), respectively, to meet the special classification needs of demographic household surveys. The Census classifications use the same basic structure as the SOC and NAICS, but are generally less detailed.

  • 2018 Census Occupation Titles and Code List (XLSX)
    • Includes a crosswalk to the 2018 SOC
  • 2017 Census Industry Titles and Code List (XLSX)
    • Includes a crosswalk to the 2017 NAICS

More information about the Census occupational and industry classifications is available from the Census Bureau, including indexes showing where specific jobs and industries are classified.

Learn more about the historical comparability of occupation and industry data from the CPS.




Population control adjustments to the CPS

Population controls are independent estimates of population used to weight the CPS sample results to reflect the civilian noninstitutional population age 16 and older.

The U.S. Census Bureau develops the CPS population controls. They are based on the latest decennial census population count, supplemented with birth and death data and estimates of net international migration. The population estimation methodology is available on the Census Bureau's website.

The Census Bureau adjusts the CPS population controls each year to include the latest information about population change and to incorporate any improvements in the estimation methodology. Following a decennial census, a new population base is introduced along with the adjustments.

BLS incorporates the annual population control adjustments into the CPS estimates with data for January.

The adjustments may increase or decrease the population level, depending on whether the latest information indicates the population estimates had trended high or low. Conceptually, the effects of the annual population control adjustments represent cumulative over- or under-estimation of the population since the last decennial census point.

See Adjustments to Household Survey Population Estimates for a description of the latest population control adjustments to the CPS, and a supplemental table with the latest adjustment effects.

Archived information on the annual population control adjustments


Additional information related to CPS population controls

  • Article: Revisions to the Current Population Survey effective in January 2003 (PDF)
  • Discussion of historical comparability, including adjustments to the population controls over time (PDF, page 5)


Labor force and employment research series smoothed for population control adjustments


Notice to Smoothed Series Data Users

BLS will no longer update the smoothed labor force and employment research series.

These series, which run from January 1990–December 2017, were last updated in February 2018. They will remain available online for interested data users, but no further extensions or revisions to the series are planned.

As a convenience to data users, BLS provided and updated the smoothed labor force and employment research series from 2003–2018. Their purpose was to aid analysis by smoothing out noneconomic level shifts that may occur in the data between December and January when the annual adjustments to survey population controls are introduced. They were developed in 2003 when the introduction of the Census 2000 population base caused substantial level shifts in the labor force and employment series.

  • Description of the labor force and employment research series smoothed for population control adjustments (PDF)
    • Table: Labor force research series smoothed for population control adjustments, seasonally adjusted (XLSX)
    • Table: Employment research series smoothed for population control adjustments, seasonally adjusted (XLSX)
  • Documentation on the methodology used to create the smoothed labor force and employment research series (PDF)



Questionnaire for the CPS

Information about the survey collection process, including the questionnaire, is available from the Census Bureau, which conducts the CPS.




Reliability of estimates from the CPS

Statistics from the CPS are subject to both sampling and nonsampling error. When a sample rather than the entire population is surveyed, there is a chance that the sample estimates may differ from the "true" population values they represent. The exact difference, or sampling error, varies depending on the particular sample selected, and this variability is measured by the standard error of the estimate.

  • Table: Changes in selected labor force indicators with a statistical significance test (updated monthly) (PDF) (HTML)
  • UPDATED October 2023 parameters and factors for calculating standard errors, tables PF-1 through PF-16 (XLSX)
  • Instructions for calculating approximate standard errors and confidence intervals for CPS estimates (PDF)
    • Standard error illustrations (XLSX)



Research

Browse recent BLS analyses of CPS data by topic: unemployment, labor force characteristics, earnings, and demographic characteristics.

Research series on earnings of nonhourly full-time workers

Survey methods research:


Response rates


Seasonal adjustment of CPS estimates

Labor force levels, employment, unemployment, and other labor market measures sharply fluctuate over the course of a year due to seasonal events such as weather, major holidays, and the opening and closing of schools. Seasonal adjustment is a statistical procedure used to remove seasonal fluctuations from data series, making it easier to observe cyclical and other economic trends. BLS produces a wide range of seasonally adjusted labor market measures from the CPS.

Current procedures for seasonally adjusting CPS data are described in the article Seasonal Adjustment Methodology for National Labor Force Statistics from the Current Population Survey.

At the end of each calendar year, the Bureau of Labor Statistics (BLS) reestimates the seasonal factors for the CPS series by including another full year of data in the estimation process. Following this annual reestimation, BLS revises the historical seasonally adjusted data for the previous 5 years.

The most recent revisions to seasonally adjusted CPS series are described in Revisions to seasonally adjusted national household survey labor force series.


Archived articles describing CPS seasonal adjustment methodology and annual updates to the seasonally adjusted series

Latest article: Revisions to seasonally adjusted national household survey labor force series

2021 2022 2023           
2020 2019 2018 2017 2016 2015 2014 2013
2012 2011 2010 2009 2008 2007 2006 2005
2004 2003 2002 – 1999 1998 – 1990

 

Research articles on CPS seasonal adjustment

  • Seasonal Adjustment of CPS Labor Force Series During the Great Recession (October 2013) (Abstract) (PDF)
  • Model-based seasonally adjusted estimates and sampling error (September 2005) (PDF)
  • An Evaluation of Concurrent Seasonal Adjustment for the Major Labor Force Series (August 1987) (PDF)

 

Last Modified Date: April 30, 2024