Until recently, the probability-based online KnowledgePanel® run by Knowledge Networks (KN) used exclusively a random-digit dial (RDD) methodology for panel recruiting. RDD-based recruitment has been rapidly losing its technical and cost-effective edge due to the increasing efforts required to achieve acceptable response and coverage rates. More importantly, the shrinking coverage of RDD frames due to the increase of cell-phone-only households and the related disproportionate loss of sample coverage for young adults and Hispanics has rendered RDD recruitment to becoming increasingly inadequate for achieving representative national samples. 

An address-based sample (ABS) frame using mail recruitment has emerged as a solution to coverage and minimizing response bias. In 2008, KN conducted a pilot study to recruit panel members via mail using the USPS Delivery Sequence File for its ABS frame. Two large-sample waves were implemented in 2009, supplementing the RDD-sourced sample. Each ABS wave has incorporated refinements to the mailing strategy based on experiments performed in the pilot in prior large-sample waves. These experiments altered materials, incentives and compressed the length of the field period without loss in response rate or sample representativeness. To enhance diversity, the second wave in 2009 included the targeting of high-density minority communities using a stratified sample. Also implemented was a plan to increase the recruitment of households that do not have Internet access. (KN supplies such households with a laptop computer and Internet access so that they, too, can participate in online surveys.) This presentation reviews data demonstrating the evolving effectiveness of KN’s mail-based recruitment strategy as evidenced by successive increases in yield and response rate; in improved sample representativeness; in targeting minority areas; and in the recruitment of non-Internet household using a targeting “message” strategy among non-responders.