In each wave, the sampling frame was constructed through a comprehensive census identifying the full population of local religious congregations. From this frame, a stratified random sample of congregations was drawn with disproportionate allocation to minority traditions; in the second wave, all congregations known to engage in environmental initiatives (“greening”) were sampled. Data were obtained from a single knowledgeable key informant in each congregation—almost always the spiritual leader—through Computer-Assisted Telephone Interviewing (CATI); in the second wave, a subset completed the survey via Computer-Assisted Web Interviewing (CAWI). Particular complexities in sampling Roman Catholic parishes are detailed in the methodological report.