Household Telephone Service and Usage Patterns in the United States in 2004 : Implications for Telephone Samples

Changes in the U.S. telephone system, especially the rapid growth in the prevalence and use of cell phones, raise concerns about undercoverage error in random digit dial (RDD) telephone samples. A supplement to the Current Population Survey (CPS) was conducted in 2004 to examine telephone service and usage in U.S. households. This article explores the potential for biases in RDD surveys resulting from the increases in cell phones by presenting estimates of the percentage of households with different types of telephone service, including the percentage of cell-only households, and giving demographic profiles of households by type of telephone service. Logistic regression models examine variables that predict whether households are without a telephone or only have cell phones. These predictors may be used for weighting adjustments to reduce undercoverage biases. We address some additional issues, including the wording of questions for measuring telephone service, that are relevant if telephone-sampling methods are revised to include cell phones. The estimates from the CPS supplement are also used to help understand some of the new sampling and weighting problems associated with selecting samples from cell phone numbers