SIPP’s complex sample design must be considered when calculating the variance of estimates. A common mistake is to treat the SIPP sample as a simple random sample (SRS) of the population, which will typically underestimate the true sampling error variances.

The SIPP data files contain variables related to the sample design that are created for the purpose of variance estimation. The Census Bureau also provides generalized variance functions (GVFs) that can be used to obtain approximate estimates of sampling variance for SIPP estimates. Finally, a set of replicate weights are also provided in order to estimate more accurate standard errors and variances for SIPP estimates. While replicate weighting methods require more computing resources, many statistical software packages have procedures that simplify the use of replicate weights for users. 

Please see the SIPP Users’ Guide specific to your year or panel of analysis for more guidance on estimating SIPP’s sampling error.