Risks and rewards of using prepaid vs. postpaid incentive checks on a survey of physicians

Survey researchers use monetary incentives as a strategy to motivate physicians’ survey participation. Experiments from general population surveys demonstrate that prepaid incentives increase response rates and lower survey administration costs relative to postpaid incentives. Experiments comparing these two incentive strategies have rarely been attempted with physician samples.

A nationally representative sample of oncologists was recruited to participate in the National Survey of Precision Medicine in Cancer Treatment. To determine the optimal strategy for survey incentives, sample members were randomly assigned to receive a $50 prepaid incentive check or a $50 promised (postpaid) incentive check. Outcome measures for this incentives experiment include cooperation rates, speed of response, check-cashing behavior, and comparison of hypothetical costs for different incentive strategies.

Cooperation rates were considerably higher for sample members in the prepaid condition (41%) than in the postpaid condition (29%). Similar differences in cooperation rates were seen for physicians when stratified by region, size of the physician’s metropolitan statistical area, specialty, and gender by age. Survey responders in the prepaid condition responded earlier in the field period than those in the postpaid condition, thus requiring fewer contacts. In the prepaid group, 84% of sample members who responded with a completed survey cashed the incentive check and only 6% of nonresponders cashed the check. In the postpaid condition, 72% of survey responders cashed the check; nonresponders were not given a check. The relatively higher cooperation rates and earlier response of the responders in the prepaid condition was associated with a 30% cost savings for the prepaid condition compared to the postpaid incentive condition.

The results of this study suggest that the rewards of offering physicians a prepaid incentive check outweigh the possible risks of nonresponders cashing the check. The relative cost benefit of this strategy is likely to vary depending on the amount of the incentive relative to the costs of additional contact attempts to nonresponders.