03 · What You Need to Know
Why Compensation and Risk Should Be Evaluated Separately
Payment Does Not Reduce the Risk Itself
If a research procedure has a 5% chance of causing a particular injury, paying the participant does not reduce that probability. The procedure remains physically risky. Likewise, payment does not make a confidentiality breach less damaging, a distressing interview less distressing, or a harmful experimental intervention less biologically hazardous.
This seems obvious, yet compensation can become misleading when researchers describe a study as though money and risk sit on opposite sides of one ledger. Ethical assessment asks whether the participant may appropriately be exposed to the risk. Compensation asks a different question about the terms under which participation is offered.
The U.S. Office for Human Research Protections has specifically stated that remuneration should not be treated as a way of offsetting research risks in the IRB's risk-benefit assessment. At the same time, OHRP recognizes that payment for participation is common and, in general, acceptable.
Compensation Can Be Legitimate
Saying that money cannot rescue unacceptable risk does not mean participants should not be paid.
Participants may spend time completing questionnaires, attending appointments, traveling to a research site, undergoing procedures, or changing their schedules. Compensation can recognize their time and effort. Reimbursement can cover reasonable expenses caused by participation. Small tokens of appreciation may also be used in some settings.
SACHRP, an advisory committee to HHS, distinguishes reimbursement, compensation, appreciation payments, and incentive payments because they serve different functions and present different ethical questions. It recommends recognizing compensation for participants' time and effort separately from reimbursement of out-of-pocket costs.
Compensation Is Not the Same as Incentive
These terms are often used interchangeably, but the distinction can be useful.
Reimbursement
Repays reasonable costs incurred because of participation, such as travel or related expenses.
Compensation
Recognizes participants' time and effort or the burdens of participation.
Incentive
Offers an additional inducement intended to make participation or retention more attractive.
These categories can overlap in real-world payment schemes, and institutions may use different terminology. The important distinction is functional: reimbursement and compensation generally address what participation costs or demands, while incentives may deliberately make participation more attractive.
Payment Can Affect Voluntariness Without Becoming “Coercion”
OHRP distinguishes payment from coercion. Coercion involves a threat or penalty that removes a person's reasonable alternative. Payment is not ordinarily coercive simply because it influences someone's decision.
The more relevant concern with an unusually large incentive may be undue influence: a payment might become so attractive in context that it interferes with a prospective participant's ability to adequately consider risks, burdens, and other reasons for or against participation.
OHRP's informed-consent guidance states that researchers should provide sufficient opportunity to consider participation and minimize the possibility of coercion or undue influence. It also notes that proposed remuneration should be just and fair and that IRBs should consider the study population and context when evaluating payment.
Large Payment Is Not Automatically Unethical
The opposite assumption is also too simple. A high payment is not automatically undue influence merely because it is high.
SACHRP emphasizes that payment can influence participation without necessarily compromising decision-making. The relevant question is whether the offer interferes with adequate consideration and understanding of important study features, including risks and burdens.
This means researchers should examine the whole context rather than assign a universal monetary threshold.
Payment Should Not Be Used to Repair a Bad Study Design
Suppose a study requires participants to remain in the laboratory for eight hours because the research team has not optimized the protocol. Increasing the payment does not fix the excessive burden. A better solution may be to shorten the session, split it into manageable visits, remove unnecessary procedures, or redesign data collection.
The same reasoning applies to risk. If an invasive procedure can be replaced by a less risky scientifically adequate method, higher compensation should not be the first response.
The appropriate sequence remains: minimize the research exposure first, then determine how participants should be fairly compensated for the participation that remains.
Compensation Does Not Make a Non-Beneficial Procedure Directly Beneficial
A participant may receive a payment after undergoing a research-only procedure. That payment does not turn the procedure into one offering a direct health benefit.
This distinction matters when assessing studies in which participants have no prospect of personal benefit. Payment may be part of a fair participation arrangement, but it does not replace the scientific and ethical justification required for the underlying procedure.
Researchers should therefore keep direct participant benefit conceptually separate from compensation.
Compensation Should Not Be Used as the Benefit Side of the Risk-Benefit Equation
The ethical problem becomes particularly clear when researchers write something like: “Participants face moderate physical risk but will receive 10,000 pesos, making the study beneficial to them.”
The payment may certainly matter to participants. It does not establish that the research procedure is beneficial to their health or welfare, nor does it demonstrate that the risk itself is justified.
The appropriate risk-benefit question remains whether the research risk is reasonable under the applicable ethical framework in relation to anticipated participant benefits, if any, and the scientific or social value of the research. Payment should be assessed separately.
Compensation and Risk Can Still Be Related in Important Ways
Separating compensation from risk does not mean pretending that money has no ethical effect. Payment can affect who enrolls, how people perceive participation, and whether they are willing to accept burdens.
It can also create concerns about equitable participation. SACHRP notes that compensation can help address participants' opportunity costs and may broaden recruitment, while also requiring attention to whether incentives could interfere with reasoned decision-making.
Payment therefore belongs in the informed-consent and recruitment analysis, even though it should not be used to mathematically offset risk.
Payment Timing Matters
The structure of payment can influence participants' decisions about whether to remain enrolled.
For lengthy studies, withholding all compensation until completion can create pressure to continue even when participants no longer wish to participate. OHRP recommends prorating payment for time and participation in longer or multi-session studies so that participants do not have to remain enrolled merely to receive compensation for work already completed.
This does not mean every completion bonus is prohibited. It means payment structures should be examined for their effects on voluntariness and the participant's ongoing ability to withdraw.
Researchers Should Be Transparent About Payment
Payment terms should be clear before enrollment. Participants should know how much they will receive, what it is intended to compensate, when it will be paid, and what happens if they withdraw before completing the study.
The 2024 Declaration of Helsinki requires research protocols to include incentives for participants and requires prospective participants to be informed about incentives as part of the consent process. It also requires participants to be told that they may refuse participation or withdraw without reprisal.
Compensation After Research-Related Injury Is a Separate Issue
There is another meaning of “compensation” in research ethics: payment or treatment for participants who are harmed as a consequence of research participation.
This should not be confused with ordinary payment for participation. The 2024 Declaration of Helsinki requires appropriate compensation and treatment for participants harmed as a result of participating in research and calls for protocols to address provisions for participants who suffer research-related harm.
Compensation after injury addresses the consequences of harm. It does not provide advance ethical permission to expose participants to an otherwise unacceptable level of risk.
Very Large Incentives Can Create a Different Ethical Problem
A large payment may be especially influential for people in severe financial circumstances. But financial vulnerability should not automatically be treated as proof that participants cannot make voluntary decisions.
OHRP and SACHRP emphasize contextual assessment. The relevant question is whether the payment could impair participants' ability to appreciate important study information or otherwise compromise voluntariness.
The ethical response should therefore not be a simplistic rule that poor people must receive low payments. Both participant protection and fair compensation matter.
Payment Cannot Convert an Unacceptable Risk Into an Acceptable One
The cleanest way to reason about the title question is to separate the stages of ethical review.
Assess the research itself
Determine whether the study has sufficient scientific and social value and whether participants need to face the proposed exposure.
Minimize the risk
Remove unnecessary procedures and use safer scientifically adequate approaches where available.
Judge the residual risk
Determine whether the remaining risk is ethically acceptable under the applicable framework.
Set fair payment
Determine appropriate reimbursement, compensation, appreciation, or incentives without treating them as a substitute for risk justification.
Check voluntariness
Ensure payment terms do not interfere with informed and voluntary decision-making or the participant's right to withdraw.
That sequence keeps compensation in its proper place. Money can make participation fairer or more practical. It cannot make an impermissible research exposure permissible by itself.
