Abstract

The combination of survey data with more objective information, such as administrative records, is a promising innovation within social science research. The advantages of such projects are manifold, but implementing them also bears challenges to be considered. For example, the survey respondents typically have to consent to the linking of external data sources and interviewers have to feel comfortable with this task. This dissertation investigates whether and to what extent the interviewers have an influence on the willingness of the respondents to participate in two new projects within the Survey of Health, Ageing and Retirement in Europe (SHARE). Both projects had the goal to reduce the burden for respondents and to increase the data quality by linking the survey data with additional, more objective data. Both linkages required the interviewers to collect respondents’ written consent during the interview. The starting point of this dissertation is the question of what influences respondents’ decisions to consent to link their survey answers with administrative data. Three different areas are considered: characteristics of the respondents, the interviewers, and the interaction between respondents and interviewers. The results suggest that although respondent and household characteristics are important, a large part of the variation is explained by the interviewers. However, the information available about interviewers in SHARE is limited to a few demographic characteristics. Therefore, it is difficult to identify key interviewer characteristics that influence the consent process. To close this research gap, a detailed interviewer survey was developed and implemented in SHARE. This survey covers four different dimensions of interviewer characteristics: interviewers’ attitudes, their own behavior, experiences in surveys and special measurements, and their expectations regarding their success. These dimensions are applied to several aspects of the survey process, such as unit or item nonresponse as well as the specific projects of the corresponding SHARE questionnaire. The information collected in the interviewer survey is then used to analyze interviewer effects on respondents’ willingness to consent to the collection of blood samples. Those samples are analyzed in a laboratory and the results linked with the survey data. Interviewers’ experience and their expectations are of special interest, because as these are two characteristics that can be influenced during interviewer training and selection. The results in this dissertation show that the interviewers have a considerable effect on respondents’ consent to the collection of biomarkers. Moreover, the information collected in the interviewer survey can explain most of the variance on the interviewer level. A motivation for linking survey data with more objective data is the assumption that survey data suffer from recall error. In the last step, the overlap of information collected in the survey and provided in the administrative records is used to analyze recall error in the year of retirement. The comparison of the two datasets shows that most of respondents remember the year they retired correctly. Nevertheless, a considerable proportion of respondents make recall errors. Characteristics can be identified which increase the likelihood of a misreport, However, the error seems to be unsystematic, meaning that no pattern of reporting the event of retirement too late or too early is found.