Comparison of Responses to a $2 Bill versus a Chance to Win $250 in a Mail Survey of Emergency Physicians

Abstract

Abstract Objectives: To evaluate whether small monetary incentives improve physicians' responses to surveys. To the best of the authors' knowledge, no one has evaluated emergency physicians' response rate and cost per participant of a small monetary incentive relative to a chance to win a more substantial sum. The authors compared emergency physicians' responses and per‐participant costs between a $2 bill and a $250 lottery. Methods:Two groups of 288 emergency physicians were randomly selected and mailed a survey. Within each group of 288, half received a $2 bill and the other half received an offer that respondents would be entered into a drawing to win $250. Nonresponders received a reminder postcard one week later, and persistent nonresponders received a second mailing of the survey three weeks after the initial mailing. Results: Of the 576 surveys that were mailed, nine (2%) subjects were ineligible or undeliverable, leaving 567 eligible subjects, of whom 301 (53%) participated in the survey. The $2 bill had a substantially higher response rate: 170 (56%) of those receiving a $2 bill participated versus 131 (44%) of those receiving a chance to win $250 (95% confidence interval = 5% to 22%; p < 0.001). The $2 bill offer was less expensive per participant than the $250 offer. The cost of postage and incentives was $997.33 for 170 participants, or $5.87 per participant, for the $2 bill and $979.29 for 131 participants, or $7.48 per participant, for the chance to win $250. Conclusions: Mailing a $2 bill incentive produces a better response rate with lower cost per participant than offering a chance to win $250.