Reading fast, reading slow: Interviewer behavior and the influence on survey outcomes

Standardized interviewing aims to reduce the interviewers’ influence as deviations might bias the data and negatively affect data quality. This project contributes to the literature on deviant interviewer behavior by analyzing the extent to which interviewers change their reading behavior across the survey’s field period, and whether this has implications for the survey outcomes. Using item-level paradata from the Survey of Health, Ageing and Retirement in Europe (SHARE), we focus our analyses on introductory items in selected modules of the questionnaire. In contrast to previous research, this enables disentangling reading and response times between interviewers and respondents. In addition, the data source allows us to carefully control for confounding effects. Based on fixed effects regressions, our results show systematic changes in interviewers’ reading times. First, interviewers’ reading times significantly decrease over the survey’s field period, even after controlling for period effects, relevant respondent characteristics, and specific aspects of the interview situation. Second, a cross-national comparison that included 14 European countries plus Israel reveals that the decrease is uniform in almost all cases, suggesting its generalizability over a wide spectrum of conditions. Third, this decrease influences survey outcomes less negatively than expected and to a varying degree depending on the informational content of the item read by the interviewer. However, it is especially relevant for within-survey requests. On the basis of these findings, we discuss possible consequences for questionnaire design as well as interviewer training and fieldwork monitoring.