Privacy effects on self-reported drug use: interactions with survey mode and respondent characteristics.

This chapter examines the impact of interview privacy on self-reported illicit drug use. In 1991, interviews were completed with an urban-suburban sample of 2,417 adults aged 18 to 45. Results show that the presence of third parties during the interview significantly influences respondents' willingness to reveal illicit drug use. Among married respondents, presence of a spouse resulted in higher reporting of illicit drug use, while the presence of adults other than the spouse had a consistent negative effect on drug use reports. A parent's presence during the interview significantly reduced respondents' willingness to report illicit drug use. The pattern of findings suggests that the direction of effects due to third party presence is linked to two factors: the extent of the third party's knowledge of the information requested, and the degree of personal stake the third party may have in the respondent's answers. The differential impact of privacy by interview mode was also examined. Tests of interactions between privacy and interview mode failed to support the hypothesis that the use of self-administered answer sheets reduces privacy effects compared with interviewer-administered interviews.