Adjusting to the Survey: How Interviewer Experience Relates to Interview Duration

Abstract

Interview duration has been shown to become shorter as fieldwork progresses. This has been attributed to a learning effect interviewers go through as they gather experience. In this study, we expand on this knowledge by focusing on how two kinds of interviewer experience relate to interview duration in telephone surveys. Using data from the German National Educational Panel Study (NEPS), we employ multilevel models, accounting for the clustering of respondents within interviewers. The results strengthen previous findings associating within-survey interviewer experience with decreasing interview duration. On the other hand, countering previous work, we find evidence that interview duration also decreases with overall interviewer experience. The results add to our knowledge concerning the effect of interviewer experience in the telephone survey mode. The effects are robust to several model specifications and to different interviewer, respondent, and interview characteristics. We conclude with a discussion about how to manage interviewer experience during training and fieldwork.