This page contains technical documentation and related information on the Current Population Survey (CPS).
Summarized documentation on the concepts and methodology of the CPS.
Comprehensive documentation on the design and methodology of the CPS, including a history of the survey (links to the Census Bureau website).
Historical comparability is affected by revisions to population controls, changes in occupational and industry classification, and other changes to the survey.
There are two monthly surveys that provide sample-based estimates of employment: the CPS, also known as the household survey, and the Current Employment Statistics (CES) survey, also known as the establishment or payroll survey. The establishment survey employment series has a smaller margin of error on the measurement of month-to-month change than the household survey because of its much larger sample size. However, the household survey has a more expansive scope than the establishment survey because it includes the self-employed, unpaid family workers, agricultural workers, and private household workers, who are excluded by the establishment survey. The household survey also provides estimates of employment for demographic groups.
Description of how the national unemployment statistics are developed from the Current Population Survey (CPS), written in non-technical language.
The Current Population 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.
In order to produce estimates from survey data, statistical weights must be applied. Population controls are independent estimates of population used to weight the CPS sample results. The population controls are developed by the U.S. Census Bureau. They are based on decennial census information, and between decennial census years they incorporate administrative data, such as birth and death statistics, along with the Census Bureau's estimates of net international migration.
The Census Bureau reviews and adjusts the population controls every year. BLS introduces the annual population control adjustments into the CPS estimates beginning with the January data. The adjustment can either increase or decrease the population level, depending on whether the latest information indicates the population estimates have trended too high or low. Conceptually, the population control adjustments represent the cumulative over- or under-estimation of the population since the last decennial census point.
The results from Census 2010 were incorporated into CPS population controls with the release of data for January 2012. CPS estimates for January 2000 through December 2011 reflect population controls based on Census 2000.
The level shifts in the CPS labor force and employment series resulting from annual population adjustments can make it difficult for data users to compare changes over time periods that include these adjustments. As a convenience to its data users, BLS created research series that smooth out the level shifts in the labor force and employment estimates resulting from the January 2000 and subsequent population control adjustments.
Information about the survey collection process, including the questionnaire, is available from the Census Bureau, which conducts 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.
Browse recent BLS analyses of CPS data by topic: unemployment, labor force characteristics, earnings, and demographic characteristics.
Over the course of a year, the size of the labor force, the levels of employment and unemployment, and other measures of labor market activity undergo sharp fluctuations due to such seasonal events as changes in weather, major holidays, and the opening and closing of schools. Because these seasonal events follow a more or less regular pattern each year, their influence on statistical trends can be eliminated by adjusting the statistics from month to month. These adjustments make it easier to observe the cyclical and other nonseasonal movements in the series. BLS regularly produces seasonally adjusted series for selected labor force data from the CPS.
Last Modified Date: April 5, 2013