Abstract

Recognizing that offers of payment to research participants can serve various purposes—reimbursement, compensation, and incentive—helps uncover differences between participants that can justify differential payment of participants within the same study. Participants with different study-related expenses will need different amounts of reimbursement to be restored to their pre-participation financial baseline. Differential compensation can be acceptable when some research participants commit more time or assume greater burdens than others, or if inter-site differences affect the value of compensation. Finally, it may be permissible to offer differential incentive payments if necessary to advance a study’s goals. We encourage investigators and Institutional Review Boards to think not only about whether to offer payment, in what amounts, and for what purpose, but also to consider whether differential payment can help promote the scientific and ethical goals of clinical research.