Comparison of up-front cash cards and checks as incentives for participation in a clinician survey: a study within a trial

BACKGROUND: Evidence is needed regarding effective incentive strategies to increase clinician survey response rates. Cash cards are increasingly used as survey incentives; they are appealing because of their convenience and because in some cases their value can be reclaimed by investigators if not used. However, their effectiveness in clinician surveys is not known. In this study within the BRCA Founder OutReach (BFOR) study, a clinical trial of population-based BRCA1/2 mutation screening, we compared the use of upfront cash cards requiring email activation versus checks as clinician survey incentives. METHODS: Participants receiving BRCA1/2 testing in the BFOR study could elect to receive their results from their primary care provider (PCP, named by the patient) or from a geneticist associated with the study. In order to understand PCPs’ knowledge, attitudes, experiences and willingness to disclose results we mailed paper surveys to the first 501 primary care providers (PCPs) in New York, Boston, Los Angeles and Philadelphia who were nominated by study participants to disclose their BRCA1/2 mutation results obtained through the study. We used alternating assignment stratified by city to assign the first 303 clinicians to receive a $50 up-front incentive as a cash card (N = 155) or check (N = 148). The cash card required PCPs to send an activation email in order to be used. We compared response rates by incentive type, adjusting for PCP characteristics and study site. RESULTS: In unadjusted analyses, PCPs who received checks were more likely to respond to the survey than those who received cash cards (54.1% versus 41.9%, p = 0.046); this remained true when we adjusted for provider characteristics (OR for checks 1.61, 95% CI 1.01, 2.59). No other clinician characteristics had a statistically significant association with response rates in adjusted analyses. When we included an interaction term for incentive type and city, the favorable impact of checks on response rates was evident only in Los Angeles and Philadelphia. CONCLUSIONS: An up-front cash card incentive requiring email activation may be less effective in eliciting clinician responses than up-front checks. However, the benefit of checks for clinician response rates may depend on clinicians’ geographic location. TRIAL REGISTRATION: ClinicalTrials.gov (NCT03351803), November 24, 2017.