Incorporating A Multi-Mode Design Into A Random-Digit-Dialing Survey

Random-digit-dialing (RDD) surveys are typically conducted using only the telephone survey mode of data collection. However, because RDD survey response rates have been declining over the past ten years it is important to examine alternatives to the single-mode approach. This paper describes a test of one multi-mode alternative conducted as part of the Behavioral Risk Factor Surveillance System (BRFSS), a monthly state-based RDD survey that measures health conditions and risk factors. In six states, a list-assisted RDD sample was selected and matched with a database of residential telephone numbers and addresses. For the sampled telephone numbers with an address match, a mail survey with telephone survey follow-up of mail nonrespondents was employed. For sampled telephone numbers with no address match, the survey was conducted by telephone alone. After discussing the design and implementation of the six-state pilot survey, including procedures for the selection of the adult respondent(s) from the sample households, we focus on response rates and respondent characteristics by mode using the ongoing, single-mode BRFSS survey in each state as a comparison sample. The paper also discusses weighting and estimation issues for multi-mode RDD designs and examines potential mode effects.