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Annual Social and Economic Supplement Household weight


ASECWTH is a 10-digit numeric variable with four implied decimals. That is, 1234567890 should be interpreted as 123456.7890. The IPUMS command files automatically divide ASECWTH by 10,000, so no further adjustment is needed.


ASECWTH is a household-level weight that should be used to generate statistics about households in March Annual Social and Economic (ASEC) Supplement data. The CPS uses a complex stratified sampling scheme, and ASECWTH must be used to produce unbiased household-level statistics from the IPUMS-CPS ASEC data. For analyses of non-ASEC data, researchers should use HWTFINL. For individual-level analyses, researchers should use WTFINL, ASECWT, or EARNWT.

ASECWTH generally has the same value as WTSUPP for the household head or reference person. Vacant housing units and households that could not be interviewed due to residents' absence or refusal to participate have a value of zero in HWTSUPP; such sampled units were included in the public use CPS data beginning in 1988.

Estimates on the entire population are prepared by projecting forward the resident population from the last available census. These projections are derived by updating the demographic census data from a number of other data sources that account for death, births and net migration. About 3 years after every census (i.e. 2003 for the 2000 Census and 2013 for the 2010 Census), the Census Bureau updates its independent population control and provides a new weight for the relevant years.

Two important points should be noted here. First, the lag between when the Census is conducted and when the CPS weights are updated is about 3 years. While the Census data are being processed, the CPS files are made available using the weighting scheme from the US Census prior to the latest Census. Second, once the files are updated, the old weights become obsolete and are replaced in the IPUMS data extract system. Published estimates from the lag years that use the old weights are not always updated. For example, 2010 poverty estimates were released in ASEC using the 2000 population controls. Once the 2010 population controls were made available, IPUMS-CPS replaced the ASEC 2010, 2011, and 2012 weights that are based on the 2000 population control with weights that are based on the 2010 population controls.

IPUMS-CPS makes available only the most up-to-date weights. The old values are available here: Old SPM and Weights Values.


Starting in 2004, ASECWTH adjusts for oversamples of Hispanic households and of non-Hispanic white households with children under age 18 in the March ASEC data. For more information, please refer to Technical Paper 66, issued jointly by the Census Bureau and the Bureau of Labor Statistics, and the CPS documentation for the March ASEC data. Prior to 1976, the data include a small number of valid negative values; thereafter, ASECWTH has only positive values.

The food security weight, FSHWTSCALE, should be used when analyzing the food security scales.

The most recent decennial Census has typically been used as the base population estimate, however, the 2020 Census was not suitable for this purpose due to the imposition of differential privacy meant that variables required for estimates and linking records to administrative data were unavailable and delays in both enumeration and data processing brought about by the COVID-19 pandemic. To deal with these challenges, a "Blended Base" population was established, combining information from multiple resources to arrive at the base population estimate historically provided by the decennial Census. For more information on the construction of the Blended Base for vintage 2021 estimates, see Methodology for the United States Population Estimates: Vintage 2021. The Census Bureau recommends using the 2020 Census-based weights when comparing the 2020 or 2021 ASEC to the 2022 and later ASEC data; these data are incorporated into IPUMS CPS REPWTP. The 2010 Census-based weights should be used when analyzing the 2020 or 2021 ASEC data with earlier years; these data can be downloaded from this page. See the Census Bureau's Guidance on Using Replicate Weights for more information.

Comparability with IPUMS-USA

ASECWTH is fully comparable with the HWTSUPP variable in the IPUMS census and ACS samples.


  • All households.


Years Jan Feb ASEC Apr May Jun Jul Aug Sep Oct Nov Dec
1962 – 2023 - - X - - - - - - - - -


This variable has no flags.

Unharmonized Variables