Representativeness and Mode Effects in the Swiss Election Study (Selects): Are Paper Surveys Still Relevant?

Abstract Web‐based surveys have gained popularity due to their cost‐effectiveness and changing participation habits, a trend accelerated by the COVID‐19 pandemic. This raises questions about the continued value of paper‐based surveys in mixed‐mode studies like the Swiss Election Study (Selects), which uses a push‐to‐web design, offering a paper questionnaire only after several reminders. It is conventionally thought that those opting for paper surveys are older and politically less engaged. Using data from the 2019 and 2023 Selects post‐election surveys, we examine mode selection by sociodemographic and political profile, comparing web and paper samples. Our findings suggest that age‐related biases have decreased in 2023, but that citizens living in a one‐person‐household and those with less political knowledge are more likely to choose the paper questionnaire than their counterparts. Thus, the added value of paper surveys in correcting selection biases remains, but especially age‐related effects are likely to become less relevant over the next years.