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Stratified Telephone Survey Designs

Robert J. Casady and James M. Lepkowski


Two stage random digit dialing procedures as developed by Mitofsky and elaborated by Waksberg are widely used in telephone sampling of the U.S. household population. Current alternative approaches have, relative to this procedure, coverage and cost deficiencies. These deficiencies are addressed through telephone sample designs which use listed number information to improve the cost-efficiency of random digit dialing. The telephone number frame is divided into a stratum in which listed number information is available at the 100-bank level and one for which no such information is available. The efficiencies of various sampling schemes for this stratified design are compared to simple random digit dialing and the Mitofsky-Waksberg technique. Gains in efficiency are demonstrated for nearly all such designs. Simplifying assumptions about the values of population parameters in each stratum are shown to have little overall impact on the estimated efficiency.