Randomized experiment on the effect of incentives and mailing strategy on response rates in a mail survey of dentists

Response rates for mail surveys of dentists and other health care providers have declined appreciably over the past several decades. The objective of this study was to update evidence about the impact use of incentives and different mail strategies on response rates in a mail survey of dentists.

We randomized private practice dentists in Iowa (N = 1267) into six study groups to test the effects of incentives and mail strategy on response rate. Survey incentives included either a $2 bill or a customized pen/stylus; a control group with no incentive was included. Mail strategies included bulk mail or first-class stamps.

The overall survey response rate was 43%. A $2 bill incentive was associated with significantly higher likelihood of returning a survey compared to the control group with no incentive (48% response rate vs. 40%, respectively). A non-monetary incentive was not significantly associated with likelihood of response. Use of first-class stamps compared to bulk mail did not significantly affect response rate.

This study demonstrated the effectiveness of a $2 incentive to increase response rate in a mail survey of dentists. Given the background trend of declining survey participation rates, researchers should consider use of monetary incentives and explore new strategies to increase participation among dentists and other health care providers.