After each popular vote at the federal level, a cross-sectional online survey is conducted among a random sample of Swiss voters (Swiss citizens aged 18 years and above) taken from the "Sampling frame for personal and household surveys" (SRPH) of the Swiss Federal Statistical Office. At the end of each cross-sectional online survey, respondents are recruited into an online panel survey, with waves after each federal vote. Only respondents with a valid email address are recruited into the feed-in panel survey.
