Substance Use Estimates From RDD and Area Probability Samples: Impact of Differential Screening Methods and Unit Nonresponse

Survey mode effects linked to unit nonresponse and screening procedures were estimated in a study of self-reported to bacco, alcohol, and illicit drug use. Two samples of the same popula tion were drawn: a random digit dial (RDD) sample with telephone screening and a multistage area probability sample with in-person screening. Respondents in both samples were interviewed by telephone to control mode of communication effects. Households with out telephones were excluded from both samples to control sample coverage effects. Although results show substantially lower response rates in the telephone survey due to screening refusals, the two survey procedures produced samples that were very similar in demographic characteristics and in substance use profiles. Differential screening operations and differential nonresponse rates between the RDD and area probability designs did not appear to be a major source of mode effects in comparing telephone and face-to-face surveys of substance use.