SPMWT is an 7-digit numeric variable.

Description

SPMWT_19RYALT is the weight variable that can be used to calculate poverty rates when using alternative versions of the Supplemental Poverty Measure (SPM) variables (that is, any SPM variable with the suffix 19RYALT). This variable is identical to SPMWT and is provided only as a convenience to users who may wish to have a complete set of all SPM alternative variables.

This variable is an identical version of SPMWT that was re-released for the 2020 ASEC which reflects methodological changes first introduced with the 2021 CPS ASEC sample. For more information, see our documentation on the re-release of the 2019 SPM research file in the 2020 ASEC that describes methodological improvements that impact SPM resource and threshold variables. The SPM reference year is the calendar year to which the income, taxes, transfers, expenses, and poverty thresholds apply.

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.

For more information on calculation of the SPM, see the Census Bureau's "The Research Supplemental Poverty Measure" report.

Comparability

This variable is comparable over time.

Universe

Flags

Unharmonized Variables