Do interviewers’ reading behaviors influence survey outcomes? Evidence from a cross-national setting

Interviewers play a fundamental role in collecting high-quality data in face-to-face surveys. Here, standardized interviewing is the gold standard in quantitative data collection, while deviations from this interviewing technique are supposed to have negative implications for survey outcomes. This paper contributes to the literature on deviant interviewer behavior by analyzing to what extent interviewers vary in their reading behavior with regard to intra-individual changes across the survey’s field period and if 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 introduction items to selected modules of the questionnaire. In contrast to previous research, this offers us the possibility to disentangle reading and response time from interviewers and respondents. In addition, the data source allows us to carefully control for confounding effects. Based on a fixed effects approach, our results show systematic changes in interviewers’ reading times. First, interviewers’ reading times significantly decrease over the survey’s field period, even when controlling for period effects, relevant respondent characteristics as well as specific aspects of the interview. Second, a cross-national comparison including 14 European countries plus Israel reveals that the decrease is uniform in nearly all of them suggesting its generalizability over a wide spectrum of conditions. Third, the 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.