Evaluating Where Overlap Occurs in a Landline and Cell Phone Dual Frame Survey
Piper DuBray
ICF Macro International
Kristie Healey
ICF Macro International
Randal ZuWallack
ICF Macro International
There are two common approaches to a landline/cell phone dual frame RDD sample: the screened approach where landline users from the cell phone sample are screened out; and the overlap approach where everyone is interviewed in the landline and cell phone samples. The Behavioral Risk Factor Surveillance System (BRFSS) began using the screened approach in 2008. In 2012 the design was modified to include dual-users who receive at least 90 percent of all calls on their cell phone. In 2011 we conducted an experiment wherein all cell-users (those with and without a landline) in 4 states were eligible to complete the BRFSS survey. We grouped respondents on a continuum according to the percentage of calls received on their cell phone: 100% landline, 90% landline/10% cell up to 10% cell/90% landline and 100% cell. Theoretically, respondents in the same usership category should be similar regardless of the sample from which they came. We will evaluate this by demographically comparing respondents reached by landline to those reached by cell for each category on the continuum. We will also evaluate the continuum distribution for the landline sample compared to the cell phone sample.
