INTERVIEW MODE EFFECTS IN SURVEYS OF DRUG AND ALCOHOL USE: A FIELD EXPERIMENT

This research explores the impact of interview mode on respondents'willingness to reveal illicit or undesirable behavior and mechanismsby which interview mode influences response tendencies. A fieldexperiment was designed to control mode effects due to samplingand screening so that the impact of response anonymity (throughuse of self-administered questionnaires ([SAQs]) and socialdistance in the interviewer-respondent relationship (telephonevs. personal communication) could be tested. Respondents aged18–45 were randomly as-signed to interview mode: telephone,face-to-face, or self-administered. Admission of illicit druguse and alcohol use was most likely in the personal mode withSAQs, slightly less likely in personal mode without SAQs, andleast likely in the telephone mode. The magnitude of the modedifferentials was larger for blacks than for whites, and largeramong respondents who are more mistrustful of others. Resultssupport the notion that response effects due to mode of interviewderive, at least in part, from interview mode differences inability to assuage respondents' confidentiality concerns. Greatersocial distance between interviewer and respondent in the telephoneinterview, compared with face-to-face communication, makes itmore difficult for the researcher to make convincing confidentialityguarantees. The response anonymity provided by SAQs also appearsto increase respondents' willingness to reveal sensitive behavior,especially among racial/ethnic minorities.