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Pooled variance stratum


STRATAPLD is the pooled variance sampling strata variable that represents the impact of the sample design stratification on the estimates of variance and standard errors. It is appropriate to use STRATAPLD instead of the annual strata variable (STRATANN) if the years included in a pooled analysis include survey years 1996-2001 or 2019-forward. For pooling data from only 2002-2018, it is appropriate to use the variable STRATANN.

For analysis, researchers need to use STRATAPLD in conjunction with PSUPLD to account for stratification and clustering when computing variance estimates with IPUMS MEPS data.


STRATAPLD should be used when users wish to pool together (aka combine) more than one year of MEPS annual data including any years before 2002 or after 2018. In most years, MEPS samples are not completely independent from one another, both because each panel is in the MEPS for two consecutive years and because households are sampled from the same geographic areas in multiple years. However, because MEPS is designed to be nationally representative in every year, multiple sample years can still be pooled. The use of STRATAPLD and PSUPLD is necessary to obtain appropriate standard errors by specifying a common variance structure.


STRATAPLD is a 4-digit numeric variable.

0000: Not in Universe


There are no comparability issues.


  • 1996-2021: All persons.


  • 1996-2021


  • No weights are available for this variable. Please refer to STRATAPLD for more information.


This variable has no flags.