Changes in Methodology for the Current Population Survey’s (CPS) Annual Social and Economic Supplement (ASEC)

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Changes in Methodology for the Current Population Survey’s (CPS) Annual Social and Economic Supplement (ASEC)

This chart is produced by the Income Statistics Branch as a convenience to our users.

Income Year	Change
1947	Data based on 1940 census population controls.
1949	Implementation of expanded income questions to show wage and salary, farm self-employment, nonfarm self-employment and all other nonearned income separately.
1952	Implementation of 1950 Census-based population controls.
1961	Implementation of first hotdeck procedure to impute missing income entries (all income data imputed if any missing). Introduction of 1960 Census-based sample design.
1962	Full implementation of 1960 Census-based sample design and population controls.
1965	Implementation of new procedures to impute missing data only.
1966	Questionnaire expanded to ask eight income questions.
1967	Implementation of a new March CPS processing system.
1971	Introduction of 1970 Census-based sample design and population controls.
1972	Full implementation of 1970 Census-based sample design.
1974	Implementation of a new March CPS processing system. Questionnaire expanded to ask 11 income questions.
1975	These estimates were derived using Pareto interpolation and may differ from published data which were derived using linear interpolation.
1976	First year medians are derived using both Pareto and linear interpolation. Prior to this year all medians were derived using linear interpolation.
1979	Implementation of 1980 Census-based population controls. Questionnaire expanded to show 27 possible values from 51 possible sources of income.
1983	Implementation of Hispanic population weighting controls and introduction of 1980 Census-based sample design.
1985	Recording of amounts for earnings from longest job increased to $299,999. Full implementation of 1980 census-based sample design.
1987	Implementation of a new March CPS processing system.
1992	Implementation of 1990 Census-based population controls.
1993	Data collection method changed from paper and pencil to computer-assisted interviewing. In addition, the March 1994 income supplement was revised to allow for the coding of different income amounts on selected questionnaire items. Limits either increased or decreased in the following categories: earnings increased to $999,999; Social Security increased to $49,999; Supplemental Security Income and public assistance increased to $24,999; veterans' benefits increased to $99,999; child support and alimony decreased to $49,999.
1994	Introduction of 1990 Census-based sample design.
1995	Full implementation of the 1990 Census-based sample design and metropolitan definitions, 7,000 household sample reduction, and revised race edits.
1999	Starting in 1999, alternative income definition 7 includes federal EIC and EIC for the nine states that use federal eligibility rules to compute the state credit as a percentage of the federal EIC. The nine states are: Iowa, Kansas, Massachusetts, Maryland, New York, Oregon, Rhode Island, Vermont, and Wisconsin. Also starting in 1999, when looking at the quintiles in the historical income series, you will notice that the 50th percentile is based on micro-sorted data and may differ from the median published in the income report which is based on linearly interpolated grouped data. The Census Bureau started using the Bureau of Labor Statistics' CPI-U-RS series as an inflation factor in income year 2000. You may access information on the CPI-U-RS series and the differences between this series and the CPI-U-X1 series at /hhes/income/income01/cpiurstxt.html
2000	There are two versions of the 2000 income data available. One version is based on the traditional sample of about 50,000 households and reflects the use of 1990 census population controls. The second version is based on a sample of 78,000 households, reflecting a 28,000 household sample expansion and the use of Census 2000 population controls. Please check the table footnotes and headnotes to ascertain which data is being displayed.
2013	The 2014 Current Population Survey Annual Social and Economic Supplement (CPS ASEC) was the source of 2013 national income and poverty estimates published in September 2014. The 2014 CPS ASEC utilized a probability split panel design to test a redesigned set of income questions. Of the approximately 98,000 addresses in the 2014 CPS ASEC production sample, a subsample of about 30,000 addresses was randomly assigned to be eligible to receive the redesigned income questions. The remaining sample (approximately 68,000 addresses) was eligible to receive the set of ASEC income questions used in previous years, referred to here as the traditional income questions. The source of calendar year 2013 data for the Income and Poverty in the United States: 2013 report is the portion of the 2014 CPS ASEC sample that received the traditional income questions. The source of calendar year 2013 data for the Income and Poverty in the United States: 2014 report is the portion of the 2014 CPS ASEC sample that received the redesigned income questions. To examine the time series and make consistent comparisons, users may need to include two estimates for calendar year 2013. Estimates based on the portion of the sample that received the traditional income questions are most appropriate for comparing with 2012 and earlier years. Estimates based on the portion of the sample that received the redesigned income questions are the most appropriate for comparing 2013 with calendar year 2014 and beyond.
2017	Implementation of an updated CPS ASEC processing system.
2020	Implementation of 2020 Census-based population controls.
2022	This year, the Census Bureau started using the Chained Consumer Price Index for all Urban Consumers (C-CPI-U), produced by the Bureau of Labor Statistics (BLS), to inflation adjust income estimates from 2000 onward. The Census Bureau continues to use the Consumer Price Index for all Urban Consumers Retroactive Series (R-CPI-U-RS), also produced by the BLS, to adjust income estimates before 2000. More information about the motivation and impacts of this decision can be found on our website at Alternative Inflation Indices for Adjusting Historical Income Estimates From the CPS ASEC (census.gov).