CSR AAPOR Presentation in New Orleans
Who needs RDD? Combining directory listings with cell phone exchanges for an alternative telephone sampling frame.
Thomas Guterbock, Center for Survey Research, University of Virginia; Abdoulaye Diop, Center for Survey Research, University of Virginia; James Ellis, University of Virginia Center for Survey Research; Trung Kien Le, Center for Survey Research, University of Virginia (firstname.lastname@example.org); John Lee Holmes, University of Virginia Center for Survey Research (email@example.com).
The traditional random-digit-dialing method (list-assisted RDD using a frame of landline phone numbers) is clearly under threat. The difficulty and costs of completing telephone surveys have increased due to rising rates of refusal and non-contact. The completeness of coverage of list-assisted RDD samples has diminished due to the proliferation of cell-phone only households. The ability of list-assisted RDD to capture young, mobile, unmarried, and minority households is thus diminishing as well. Increasingly, survey researchers have been adding a cell phone component to their sampling frames for telephone surveys, despite the increased costs and other issues associated with RDD calling of cell phones. Recent research by Guterbock, Oldendick, and others has explored the extent to which 'electronic white pages' (EWP) samples really differ from RDD samples. Recently, Zogby has released results asserting that these differences are often small and ignorable. In contrast, Oldendick et al. and Guterbock, Diop and Holian have emphasized that minority households are seriously underrepresented in EWP samples. Nevertheless, EWP samples have distinct advantages whenever a survey is aimed at a restricted geographic area. This paper considers the feasibility of combining EWP samples with cell-phone RDD, eliminating the ordinary RDD component from the sampling frame. We analyze the components of the telephone population, showing that the proposed method would fail to cover only one segment of the telephone population: unlisted landline households that have no cell phone. We analyze data, primarily results from the 2005 National Health Interview Study, to estimate the size of this segment, its demographic profile, and the degree to which its demographic and health behavior characteristics are different from those in the segments that this sampling strategy would capture. Results suggest that EWP combined with cell-phone RDD can provide an efficient telephone sampling frame that would introduce little coverage bias in survey results.