Exploring the Effects of Interviewer- and Self-Administered Survey Modes on Record Linkage Consent Rates and Bias

In an effort to reduce data collection costs survey organizations are considering more cost-effective means of data collection. Such means include greater use of self-administered interview modes and acquiring substantive information from external administrative records conditional on respondent consent. Yet, little is known regarding the implications of requesting record linkage consent under self-administered survey modes with respect to consent rates and consent bias. To address this knowledge gap, we report results from a linkage consent study in which employees in an employment survey were randomly assigned to an interviewer-administered (face-to-face) or self-administered (mail/web) interview, which included a consent question to link to federal employment records. We observed a strikingly lower linkage consent rate in the self-administered (53.9 percent) versus the interviewer-administered (93.9 percent) survey mode. However, the impact of survey mode on linkage consent bias was much less severe: survey-measured correlates of linkage consent did not interact with mode and relative consent biases in the linked-administrative variables tended to be small (less than 6 percentage points) under both mode groups; though, linkage consent biases in the administrative variables were larger in the self-administered mode group compared to the interviewer-administered mode group, on average. We discuss the implications of these findings for survey practice and speculate on their possible causes.