A monetary incentive increases postal survey response rates for pharmacists

Background: Achieving acceptable response rates from health care providers via postal questionnaires is an ongoing challenge. The use of monetary incentives is one of the most effective strategies for increasing response rates. However, the effect and cost of such an incentive on retail pharmacists' response rates has not been well studied. Methods: A sample of 700 pharmacies was selected at random from the electronic Yellow Pages in NSW Australia and mailed a brief survey regarding pharmacotherapies and advice for smoking cessation. Half of the sample was randomly allocated to receive an offer of an US$14 gift voucher. Results: The response rates were 65.9% for the voucher group and 53.5% for the no-voucher group. The odds of response from the voucher group was 1.68 (95%CI = 1.23, 2.30) times greater than for the no-voucher group. The cost per additional respondent was US$67.95. The incentive also reduced follow up costs by 10%. Conclusions: A moderately sized monetary incentive is able to achieve a significant increase in response rates for retail pharmacists, thereby reducing potential bias in the sample.