Appendix: Survey methodology
The random-digit-dial survey (RDD) was conducted according to Pew Research Center’s standard protocol for RDD surveys. Interviewing occurred April 25 through May 1, 2018, with 1,503 adults living in the U.S., including 376 respondents on a landline telephone (25% of the total) and 1,127 on a cellphone (75%). The parallel registration-based sampling survey interviewed 1,854 […]