UWSC researchers along with collaborators at UW-Madison and the Max Planck Institute for Demographic Research recently published findings in Public Opinion Quarterly of two studies designed to examine the effect of sequential prepaid incentives and envelope messaging on response rates and costs in address-based mail surveys.
In the first study, sample members were randomly assigned to groups that either received a first incentive of $2 and a second one of $5 or a first incentive of $0 and a second of $2. They also received an envelope with no message or a monetary-focused message. Results indicated only the $5 preincentive was effective in increasing participation. Based on these findings a second study altered the experiment such that the amount of the second incentive was higher than the first: Respondents received a $2 preincentive and a $5 second incentive. The second study also manipulated envelope messaging by including a monetary- or health-focused message or no message. Results showed no effect of envelope messaging but a significant increase in response rates associated with a higher valued second incentive.
“If response rates are lagging and funds available, sending nonresponders a second incentive that is larger than the preincentive may increase response, but at a nontrivial cost,” suggest the authors. (Users within the UW system can download the article at http://poq.oxfordjournals.org/content/79/4/906.full.pdf+html; others should contact Jennifer Dykema (email@example.com), for a copy of the paper.)