In the Understanding America Study (UAS), sample weights are survey-specific. They are provided with each completed UAS survey and, unless otherwise specified, are meant to make each survey data set representative of the U.S. population aged 18 and older with respect to a pre-defined set of socio-demographic variables. Sample weights are constructed in two steps. The first step concerns the computation of base weights, which correct for unequal probabilities of sampling UAS members. In a second step, final post-stratification weights are generated, allowing the sample of each study to align with the reference population along certain socio-demographic dimensions.

Sample weights are constructed for all UAS panel members, except for two small sub-groups. Specifically, respondents recruited through Native American batches (recruitment batches 2 and 3) who are not Native Americans and respondents recruited from a list of women who had given birth in Los Angeles County between 2009 and 2012 (recruitment batch 4) receive zero base weight and zero final post-stratification weight.

Detailed information about the UAS weighting procedures can be found in the UAS Weighting Procedures Guide (download pdf). For questions about these procedures or if a weighted data set is not yet available for a survey, please email