How to Increase Survey Response and Manage the Postal and Face-to-Face Field Work of Participant Recruitment during the COVID-19 Pandemic : A Note with Preliminary Evidence from Immigrant-Origin and Native Voters in a German Metropolis in Spring 2021

This note presents preliminary evidence from a postal and face-to-face recruitment field for a telephone survey during the COVID-19 pandemic. Drawn from the city register of Duisburg, a metropolis of 500,000 inhabitants, voters eligible for the September 2021 Bundestag elections are the target population. They are stratified into four groups by onomastic classification: native Germans, Germans of Turkish Descent, Germans with a (Post-) Soviet background and Germans of any other immigrant origin. This note presents ten measures of optimising the recruitment of individuals from these four groups under the constraints of an all-encompassing high-incidence pandemic with distance measures and curfews in place, with closed shops and schools and reduced other care facilities. In addition, the report puts forward statistical analyses of some measures applied in an experimental design and estimates the overall and per-person-recruited costs. Overall, the pandemic forced us to make drastic changes to research design and field organisation and to invest much more time and money than planned. Especially overburdened postal deliveries and restrictive policies for public places made the endeavour most difficult. So far, the ongoing fieldwork has produced a response rate of 8.2 % (only individuals willing to participate in telephone interview) with 11.0 % as a likely expected outcome. One individual recruited to take part in the telephone panel survey costs an estimated 53-71 €.Early-bird incentives produced a positive response (meaning the willingness to partake in the survey) of 5.5 % compared to 4.0 % among those without early-bird incentives. The most effective measure to boost overall positive response among initial non-responders was in-person canvassing with unconditional incentive (21.3 %) instead of postal reminders (9.9 %). Canvassing a smaller group of people in person proved to be as costly as reminding a larger group of people in writing: we estimated costs of 60-61 € per additionally recruited survey participants through either channel