Recruiting Probability Samples for a Multi-Mode Research Panel with Internet and Mail Components

Survey response rates have been declining over the past several decades, particularly for random-digit-dialing (RDD) telephone surveys (see de Leeuw and de Heer 2002; Steeh 1981). This trend af- fects research panels such as the Gallup Panel, which uses RDD methodology to recruit its members. If significant improvements in pan- el recruitment response rates are to be achieved, new approaches must be considered. This paper presents the findings of a mail and telephone mode experiment conducted by the Gallup Panel to analyze the individ- ual and combined effects of incentives, advance letters, and follow-up telephone calls on the panel recruitment response rate. Study results in- dicate that the mail recruitment approach nets a higher panel response rate, and that the cost-effectiveness of the mail recruitment approach is significantly greater than the telephone recruitment approach. Study re- sults also suggest that the advance letter, incentive, and telephone follow-up conditions all have independent, positive influences on the response rate; and that the groups that receive an advance letter, that receive incentives, and that receive a follow-up telephone call have higher panel recruitment response rates than the control group.