Comparing the Mobilising Effects of In-Person Canvassing to Postal Reminders -- Experimental Evidence from a Longitudinal Election Study

For hard-to-survey populations such as ethnic minorities and immigrants, increasing survey response rates is a crucial element of the fieldwork as these populations often show a higher likelihood of not participating compared with the native population. However, no study has so far compared different strategies for mobilisation within this group. Using data from the Immigrant German Election Study II, this experiment systematically compares the effects of home visits and postal reminders for the mobilisation of immigrant-origin non-respondents (i.e. persons classified as being from Turkey or from the former Soviet Union and its successor states) from a randomly drawn sample regarding the likelihood of participation in the first wave, signing up for a multi-wave panel, and taking part in all three panel waves. Multivariate analyses show that those in the treated home-visit group were more likely to take part in all stages of the survey design. Even though costs are higher than conventional postal reminders, home visits might be a useful strategy for cases in which increasing the response rate is an important goal, given a fixed, small number of potential respondents.