1968 - 2009: 99 = NIU (Not in universe)

Description

SPMNPERS records the total number of persons in the family unit used to calculate the Supplemental Poverty Measure (SPM). SPM family units differ from the family units used to calculate official poverty and are identified in SPMFAMUNIT.

SPM variables prior to 2010 are created by Columbia University's Center on Poverty and Social Research. Details about the methodology used by CPSP to construct the Historical SPM are described in the Historical SPM user note.

Comparability

Prior to 2010, SPM variables are constructed by CPSP using data from the CPS ASEC and other sources to calculate household resources and poverty thresholds. These variables are created using the best possible data available, but some must be imputed due to incomplete data coverage (particularly in the earliest years of the Historical SPM). Users are encouraged to read the Historical SPM documentation for information about CPSP's methodology and use caution when comparing pre- and post-2010 values.

SPMNPERS is comparable across years 2010 to 2018.

In 2019, the Census Bureau implemented a new processing system to accommodate survey changes. These changes affect income and relationship variables, making poverty measurements before and after 2019 incomparable. For more information on this overhaul, see our guide to the 2019 ASEC updates.

In 2020, the Census re-released the SPM Research File with revised SPM variables which incorporated improved methodology (which was originally introduced with the 2021 ASEC file). This variable contains the originally released SPM variable data, not the revised data. IPUMS created alternative SPM variables for the 2020 sample. For information on these alternative SPM variables in the 2020 ASEC, see our documentation on the re-release of the 2019 SPM research file in the 2020 ASEC that lists all revised variables and describes methodological improvements that impact SPM resource and threshold variables.

Universe

Flags

Unharmonized Variables