Impact of Incentives on Physician Participation in Research Surveys: Randomized Experiment

Background: Web-based surveys can be effective data collection instruments; however, participation is notoriously low,particularly among professionals such as physicians. Few studies have explored the impact of varying amounts of monetaryincentives on survey completion. Objective: This study aims to conduct a randomized study to assess how different incentive amounts influenced surveyparticipation among neurologists in the United States. Methods: We distributed a web-based survey using standardized email text to 21,753 individuals randomly divided into 5 equalgroups (approximate to 4351 per group). In phase 1, each group was assigned to receive either nothing or a gift card for US $10, $20, $50, or$75, which was noted in the email subject and text. After 4 reminders, phase 2 began and each remaining individual was offereda US $75 gift card to complete the survey. We calculated and compared the proportions who completed the survey by phase 1arm, both before and after the incentive change, using a chi-square test. As a secondary outcome, we also looked at surveyparticipation as opposed to completion. Results: For the 20,820 emails delivered, 879 (4.2%) recipients completed the survey; of the 879 recipients, 622 (70.8%) wereneurologists. Among the neurologists, most were male (412/622, 66.2%), White (430/622, 69.1%), non-Hispanic (592/622,95.2%), graduates of American medical schools (465/622, 74.8%), and board certified (598/622, 96.1%). A total of 39.7%(247/622) completed their neurology residency more than 20 years ago, and 62.4% (388/622) practiced in an urban setting. Forphase 1, the proportions of respondents completing the survey increased as the incentive amount increased (46/4185, 1.1%;76/4165, 1.8%; 86/4160, 2.1%; 104/4162, 2.5%; and 119/4148, 2.9%, for US $0, $10, $20, $50, and $75, respectively; P<.001).In phase 2, the survey completion rate for the former US $0 arm increased to 3% (116/3928). Those originally offered US $10,$20, $50, and $75 who had not yet participated were less likely to participate compared with the former US $0 arm (116/3928,3%; 90/3936, 2.3%; 80/3902, 2.1%; 88/3845, 2.3%; and 74/3878, 1.9%, for US $0, $10, $20, $50, and $75, respectively; P=.03).For our secondary outcome of survey participation, a trend similar to that of survey completion was observed in phase 1 (55/4185,1.3%; 85/4165, 2%; 96/4160, 2.3%; 118/4162, 2.8%; and 135/4148, 3.3%, for US $0, $10, $20, $50, and $75, respectively;P<.001) and phase 2 (116/3928, 3%; 90/3936, 2.3%; 80/3902, 2.1%; 88/3845, 2.3%; and 86/3845, 2.2%, for US $0, $10, $20,$50, and $75, respectively; P=.10). Conclusions: As expected, monetary incentives can boost physician survey participation and completion, with a positive correlation between the amount offered and participation