EFFECTS OF INTERVIEW MODE ON SELF-REPORTED DRUG USE

The effects of interview mode on 18- to 34-year-olds' self-reportedtobacco, alcohol, marijuna, and cocaine use were investigated.RDD telephone and personal drug use surveys of the state ofNew Jersey were conducted in 1986–87. In the personalinterview, respondents recorded their drug use on self-administratedanswer sheets. Compared to the area probability sample in thepersonal interview, RDD yielded a sample of blacks higher inincome and education, and more likely to be married and currentlyemployed; white SES was also higher in the telephone sample,but to a lesser degree than for blacks. Controlling for demographiccharacteristics and RDD's exclusion of non-telephone households,the telephone survey yielded significantly lower estimates ofblacks' alcohol consumption, and lifetime and recent marijuanause. Whites' alcohol consumption was slightly lower by telephone;otherwise, estimates of whites' use of the four substances werenearly identical in the two modes. Sample coverage, respondentdemographic characteristics, and racial matching of interviewerand respondent did not account for the significant mode differences.Characteristics of the interview situation itself, such as provisionof privacy in the self-administered format, may have influencedtendencies toward socially desirable responding to a threateningtopic such as drug use.