Does it pay to pay? A randomized trial of prepaid financial incentives and lottery incentives in surveys of nonphysician healthcare professionals

Background: Monetary incentives in survey research may provide important gains from a methodological perspective in the control and reduction of survey error associated with potential nonresponse of participants. However, few studies have systematically investigated the use of monetary incentives or other methods to improve the response rates in the nonphysician clinician population. Objective: To investigate differences in response rates to a mailed self-administered survey of nonphysician clinicians who were randomized to receive a prepaid monetary incentive, a postsurvey prize drawing, or no incentive. Methods: A randomized controlled trial of financial incentives was conducted from November 2002 to February 2003. Nonphysician clinicians (nurse practitioners [NPs] and physician assistants [PAs]; N = 3,900) randomly selected to participate in a national ethics-related study were assigned randomly in equal allocations (n = 1,300 [650 NPs, 650 PAs]) to three incentive groups: (a) no incentive; (b) a $5 prepaid token incentive in the initial mailing; or (c) a chance to win one of ten $100 prize drawings upon completion and return of a self-administered survey. Results: A $5 cash incentive increased survey response rates to an adjusted 64.2 %: a 19.5 percentage point increase over the lottery group (44.7 % response rate), and a 22 percentage point increase over the control group (42.2 % response rate). Discussion: A nominal cash incentive of $5 yields a significantly higher response rate from nonphysician providers than receiving either a lottery option or no incentive.