Asking for Consent to be Recontacted in Surveys: Opt-in, Opt-out, or Choice?

Abstract

It may be necessary that survey respondents must be asked for consent to recontact for follow-up surveys. In this paper, we compare three options to ask for consent: choice (yes/no), opt-in, and opt-out. We analyse consent rates and compare consenters with non-consenters with respect to a comprehensive set of socio-demographic characteristics, political attitudes, and survey-related variables in a probability-based online panel survey. In a second step, we analyse consenters’ actual participation in the first follow-up survey. We find few differences between giving consent and actual participation in the first follow-up wave. For both, the opt-out option has higher response rates than the other two options. Both consenters and participants in the first follow-up wave are most similar to non-consenters in the opt-in design, closely followed by the opt-out design. Compared with opt-in and choice, there are more people in the opt-out design with low political interest, nonvoters, and who find the survey uninteresting; groups typically underrepresented in surveys. These findings speak in favour of the opt-out design.