Acceso usuarios
As researchers increasingly use mail survey methods to collect health and other data, research focused on optimizing features of survey design and administration in cost-effective ways is needed. We conducted two studies to examine the effects of sequential prepaid incentives and envelope messaging on response rates, item nonresponse, and costs in two mail surveys using address-based samples. Sample members in study 1 were randomly assigned to groups that received a preincentive of $2 versus $5, a second incentive of $0 versus $2 (sent only to nonresponders), and an envelope bearing 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 delivered a $2 preincentive to all sample members, but increased the amount of the second incentive to $5. Study 2 also tested a health-focused envelope message. While envelope messaging again failed to motivate participation, the administration of a second incentive, valued at a larger amount than the preincentive, significantly increased response rates. With regard to their effects on item nonresponse, while none of the variables was associated with item-missing levels in study 2, a significant three-way interaction was found in study 1 such that missing data was higher in the presence of a monetary message when a $2 preincentive was paired with a $2 second incentive. Cost analyses indicated that while larger incentives increased response rates, they also increased costs
