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Availability
2005-2009
Universe
All persons.
Codes
Description
REPWTP provides 160 separate person-level weights that allow users to generate empirically derived standard errors. Household-level replicate weights are available in REPWT.
More information about replicate weight creation and use is available on the IPUMS-CPS replicate weights FAQ page and in the Census Bureau's "Estimating ASEC Variances with Replicate Weights" document.
Calculating the standard error of an estimate enables the construction of a confidence interval around the sample estimate of interest and may also be used in hypothesis testing. In theory, the standard error of an estimate measures the variation of a statistic across multiple samples of a given population. Researchers can use replicate weights to mirror this theoretical approach when only sample data is available, and the resulting standard errors have a higher degree of precision than standard asymptotic standard errors.
The 2005-onward CPS samples contain 160 replicate weights at the person level (variables named REPWTP1 through REPWTP160). For self-representing strata (i.e., areas with populations large enough to be represented with certainty in the sample), the replicate weights were produced using what is known as the successive difference replication (SDR) method. For non-self-representing strata (areas that are not represented with certainty in the sample), the replicate weights were produced using the modified half-sample technique. Both methods involve repeated implementations of the initial (full-sample) weighting algorithm, such that full information about the CPS sample is available in the replicate weights. Nevertheless, users should use these replicate weights only for generating variance estimates, not for obtaining unique parameter estimates.
User Note: The successive difference replication approach (SDR) is different from other methods for creating replicate weights such as balanced repeated replication (BRR) and jackknife estimation, and standard statistical software packages have no built-in method to handle them. However, Stata's jackknife standard error program can be adapted to calculate replicate standard errors for CPS data; see the IPUMS-CPS replicate weights FAQ for details.
Additionally, it is possible for replicate weights to take negative values for certain cases; again, users should use these weights only for variance estimation purposes and not to obtain independent estimates.
Comparability — General
Replicate weights are only available for the 2005-2009 samples of the CPS.
Comparability with IPUMS-USA
The person-level replicate weights are, broadly speaking, comparable to the person-level replicate weights in the ACS and PRCS samples 2005 and later. However, the details of the replicate weight calculations differ for non-self-representing CPS strata. Additionally, ACS/PRCS replicate weights are integers, while CPS replicate weights are not.
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