May 18, 2006

A Cell Phone Solution: Supplementing RDD Samples with Cell Phone Interviews

The past several years have seen a marked shift in the demographic makeup of random digit dial (RDD) telephone samples. Even with landline penetration at more than 90 percent, evidence strongly suggests that the people we are able to reach on a landline telephone today differ significantly from the people we could reach just 10 years ago. This shift away from traditional landline telephones is happening at the same time that cellular phone usage is on the rise. This increasing dependence on cell phones likely accounts, at least in part, for the declining numbers of young adults captured in traditional RDD samples. Our initial findings indicate that a combination of RDD and cell phone samples provides a more representative group of U.S. adults than either sample does alone and that this approach may be warranted in studies focused on internet use.