Evaluating the Effects of Screening for Telephone Service

Abstract The high costs and largely unknown error properties of cellular telephone interviews make screening for cell-only adults a po-tentially attractive option in dual frame RDD surveys. Screening out adults with landline telephones from the cellular sample does not affect the coverage properties of a dual frame survey, but it may affect other sources of error, especially nonresponse. In this study, data from a 2006 dual frame RDD survey conducted for the Pew Research Center, the As-sociated Press, and AOL are used to evaluate the effects of implementing a cell-only screener on both the bias and variance of weighted survey estimates. The effect of screening appears to be minimal so long as an adjustment for telephone service is included in the weighting method. Results of an attempt to correct for residual nonresponse due to inacces-sibility are also discussed. The potential for coverage error stemming from the exponential growth of the cell phone only population (Blumberg and Luke 2007) has led to the devel-opment of dual frame, random digit dial (RDD) surveys. In these dual frame designs, a traditional sample from the landline RDD frame is supplemented with an independent sample from the banks of numbers designated for cellular phones. The emergence of this new approach to telephone survey design has raised numerous statistical questions as well as operational ones. A critical decision, with implications for both survey costs and errors, is whether or not to screen for cell-only persons (or households) in the cellular sample (Fleeman 2006). A cell-only screener is implemented by asking respondents reached in the cellular sample whether or not they also have a landline. Persons with bot