Relevance & Research Question: It is a well-known fact that sensitive questions such as the income question show an increased item nonresponse compared to other survey questions. Less is known about how such questions affect the decision process of respondents to join a panel for follow-up surveys. Hence, the study examines in a split experiment whether there are differences concerning the recruitment success for a panel when the income question is asked or omitted during the recruitment interview. Furthermore, it investigates if those respondents, who reject to answer the sensitive question, tend to reject the panel request more often. The main question is: Are respondents affected by the sensitive question itself or is there a general lower trustworthiness among some respondents which influences both unit nonresponse in sensitive questions and the rejection of panel participation?
Methods & Data: The interview for panel recruitment is conducted via telephone with a probability sample. In a randomized split experiment half of the respondents are asked about their net household income in the recruitment interview and the other half are not asked any income information. At the end of the interview all respondents are asked whether they would be willing to join an online panel and answer questions about life in Germany via online questionnaires on a monthly basis. For this, respondents have to provide an e-mail address in the end of the telephone interview. The dependent variable is the willingness to participate in the online panel.
Results: Our previous research shows that 47% of those who answer the income question are willing to participate in an online-follow-up survey. In contrast, this figure plunges to only 22% for those who decline to provide income information (total n=818). Data collection for the current study starts in December 2010.
Added Value: The anticipated results will give insights in the (offline) recruitment process for an online panel which is based on a probability sample. The knowledge about how sensitive questions can affect later decisions of participation is crucial for designing a recruitment process, especially when sensitive questions are an important predictor in estimations of nonresponse bias.