Effects of Sequential Prepaid Incentives on Response Rates, Data Quality, Sample Representativeness, and Costs in a Mail Survey of Physicians.

While collecting high quality data from physicians is critical, response rates for physician surveys are frequently low. A proven method for increasing response in mail surveys is to provide a small, prepaid monetary incentive in the initial mailing. More recently, researchers have begun experimenting with adding a second cash incentive in a follow-up contact in order to increase participation among more reluctant respondents. To assess the effects of sequential incentives on response rates, data quality, sample representativeness, and costs, physicians (N = 1,500) were randomly assigned to treatments that crossed the amount of a first ($5 or $10) and second ($0, $5, or $10) incentive to form the following groups: Group $5/$5; Group $5/$10; Group $10/$0; Group $10/$5; and Group $10/$10. Overall, second incentives were associated with higher response rates and lower costs per completed survey, and while they had no effect on item nonresponse, they increased sample representativeness.