A Minimally Intrusive Method for Sampling Persons in Random Digit Dial Surveys

To survey a population of persons such as all adults, many studies sample households as an intermediary step to reach this population because directly sampling persons requires a comprehensive list that exists only in specialized situations. In random digit dial (RDD) surveys, the sample of households is obtained by sampling telephone numbers. Within-household sampling is then performed to go from the household to the person level. From the earliest days of conducting RDD surveys, a key research objective has been the development and evaluation of methods of within-household sampling that do not lower response rates. Some sampling methods that do not give probability samples have been proposed and used in practice. Although these methods are subject to selection bias, their use has been justified as necessary to increase response rates by simplifying and improving the flow of the interview. We propose a new and simple method of within-household sampling that is minimally intrusive and, thus, should not have a deleterious effect on response rates. The method results in a probability sample of eligible persons within households. The method is especially simple to implement in computerassisted telephone interview (CATI) RDD surveys. We focus on sampling one adult from each household as this is the primary application, but we also describe how the method can be extended to sample more than one person per household. This paper provides an introduction to the method and results from one study. Experimental comparisons of this approach with other methods of within-household sampling would be a useful next step.