Weighting Procedures for Dual Frame Telephone Surveys: A Case Study in Egypt

Abstract

Although it is a quick and non-expensive tool used to collect survey data in Egypt, the landline telephone surveys cannot reach the non-landline households, which makes up 73.4 percent of the households in Egypt according to the 2012/2013 Egypt - Household Income, Expenditure, and Consumption Survey (HIECS). Therefore, among other centers, the Public Opinion Poll Center (POPC) adopted the dual frame telephone surveys as an alternative to the landline telephone surveys, in which the landline sample is supplemented by a Pseudo-Random-Digit-Dial (Pseudo-RDD) sample of cell phones. The cell phone sample can reach the cell-only households (households with no landline but are accessible by cell phone), about 66.7 percent, based on the 2012/2013 Egypt HIECS data; this contributes to reducing the potential coverage bias due to not covering these households in the landline telephone surveys. Although both are telephone samples, different weighting procedures may apply for each sample. Moreover, the overlapping between the two sampling frame should be properly identified and adjusted in the weighting procedures. In this paper, sampling design and weighting procedures for the dual frame telephone surveys in Egypt will be discussed. Data from the Current Issues Survey, conducted by the POPC in October 2014, will be used as a case study to illustrate the weighting procedures and to support our discussions.