Pew Research Center · Princeton Survey Research Associates International (PSRAI)
Between March 17 and May 6, 2015, Pew recontacted 5,000 respondents from the main 2014 Religious Landscape Study, sorted into 15 strata by religious and demographic characteristics (oversampling groups like the religiously intermarried) and reweighted afterward to restore proper proportions. It shares respondent IDs and key variables (RELTRAD, CHRELTRAD, region) with the main 2014 file, so the two can be merged. It underlies the report "One-in-Five U.S. Adults Were Raised in Interfaith Homes."