SHOW Me the Money? Effects of Preincentives, Differential Incentives, and Envelope Messaging in an ABS Mail Survey
Kristen Cyffka
U.S. Census Bureau
Jennifer Dykema
University of Wisconsin Survey Center
Kelly Elver
University of Wisconsin Survey Center
Rae Ganci
University of Wisconsin Survey Center
Karen Jaques
University of Wisconsin Survey Center
John Stevenson
University of Wisconsin Survey Center
As researchers increasingly use mail survey methods to collect health data, research focused on optimizing features of their design and administration in cost-effective ways are needed. We conducted two studies to examine the effects of preincentives, differential incentives, and envelope messaging on response rates and costs in a mail survey using an address-based sample. Sample members in Study 1 were randomly assigned to groups that received a preincentive of either $2 or $5, a second incentive of either $0 or $2 (sent only to nonresponders), and an envelope bearing either no message or a monetary-focused message. Results indicated that the $5 preincentive significantly increased response rates, but neither the second incentive nor the message had an effect. Informed by the results of Study 1, Study 2 included a $2 preincentive for all sample members, but increased the amount of the second incentive to $5. Study 2 also tested the addition of a health-focused envelope message. While the message again had no effect on response rates, the second incentive significantly increased them. With regard to their effects on costs, while larger incentives increased response rates, their inclusion generally increased total costs and costs per complete.
