01 · The Question
What Should Determine How Much a Research Participant Is Paid?
A participant spends three hours at a research site. Another spends the same three hours but undergoes more inconvenient procedures. A third faces greater research risk.
Should all three receive the same amount?
Time is an intuitive basis for compensation, but it does not capture everything participants experience. Inconvenience and burden also matter. Risk is harder. Major research-ethics authorities agree that payment cannot make unacceptable research risk acceptable, but they do not frame compensation for accepting risk identically.
The result is not a universal formula of "time + inconvenience + risk." Researchers need to separate these concepts before deciding which ones legitimately belong in their payment rationale.
03 · What You Need to Know
Time, Inconvenience, and Risk Are Not Interchangeable
Time Is the Most Straightforward Starting Point
Time is observable and comparatively easy to estimate. Researchers can calculate how long participants spend completing interviews, surveys, laboratory procedures, study visits, diaries, training, follow-up assessments, or other required activities.
CIOMS states that participants in health-related research should be reasonably compensated for time spent and inconvenience. Its Guideline 13 further recommends that compensation be proportional to time spent for research purposes and travel to the research site, using the minimum hourly wage in the relevant region or country as a reference value.
SACHRP likewise identifies participants' contribution of time as a legitimate basis for compensation and discusses payment partly in relation to the opportunity costs created when research replaces other ways participants might have spent their time.
An Hour Is Not Always Just an Hour
Time alone can nevertheless be a blunt measure.
Compare spending one hour answering ordinary questions online with spending one hour fasting, traveling to a laboratory, undergoing repeated measurements, maintaining an uncomfortable position, or completing demanding cognitive tasks.
The clock records sixty minutes in both cases. The participant experience differs substantially.
This is why authoritative guidance does not reduce compensation to elapsed time. FDA explicitly lists time, inconvenience, and discomfort among the considerations that can arise when determining what participants should receive payment for.
Inconvenience Captures Burdens That Time Alone Misses
Inconvenience can include disruptions and demands created by participation even when they are difficult to price precisely.
Participants might need to fast, rearrange work, make repeated trips, attend appointments at inconvenient hours, follow dietary restrictions, wear monitoring equipment, complete daily logs, wait between procedures, or alter ordinary routines.
CIOMS expressly recognizes inconvenience alongside time as a legitimate basis for compensation in health-related research. SACHRP similarly describes compensation as addressing participants' time, effort, research-related burdens, and inconvenience.
Time
How much of the participant's time the research requires.
Inconvenience or burden
What participation disrupts, demands, or requires beyond simply occupying time.
Expenses Are a Separate Question
A participant who pays for transportation, parking, accommodation, childcare, or another qualifying study-related expense experiences a financial cost. That cost is conceptually different from the inconvenience of traveling or the time spent traveling.
CIOMS calls for reasonable reimbursement of directly incurred research costs. FDA similarly distinguishes reasonable travel and lodging reimbursement from other payment for participation.
Keeping reimbursement separate from compensation makes the payment rationale easier to interpret.
Discomfort Sits Between Inconvenience and Risk
Discomfort complicates the tidy categories.
A lengthy questionnaire can be inconvenient without posing meaningful physical risk. A blood draw can involve transient discomfort and some risk. A burdensome procedure may involve both.
FDA specifically asks what participants should receive payment for, giving time, inconvenience, and discomfort as examples. SACHRP discusses compensation for burdens and inconvenience rather than requiring a rigid distinction among every unpleasant aspect of participation.
Researchers should therefore describe the actual burden rather than assuming that every unpleasant experience belongs under "risk."
Risk Is Ethically Different Because It Must Already Be Acceptable
Research risk cannot simply be priced like participant time.
Before payment enters the equation, an ethics committee must determine whether the study's risks are ethically acceptable under the standards governing the research. FDA explicitly states that participant payment is not considered a research benefit when weighing benefits against risks.
OHRP likewise continues to maintain that IRBs should not consider remuneration as a way of offsetting risk when deciding whether research should be approved.
Watch Out
"We can expose participants to more risk because we are paying them more" is not an acceptable risk-benefit rationale. The research risk must be ethically acceptable independently of participant payment.
CIOMS Says Compensation Is Not for Accepting Risk
CIOMS takes an explicit position in Guideline 13 for health-related research: compensation is intended for inconvenience and time, not for the risk participants agree to undertake. It further states that compensation should not become so large that participants consent against their better judgment.
Under this framework, greater research risk does not itself justify a higher compensation rate. Researchers would instead compensate relevant time and inconvenience while the ethics committee separately evaluates whether the risk is permissible.
OHRP Takes a More Permissive Position on Risk-Related Remuneration
OHRP's position requires a different nuance.
In 2013, OHRP revised its informed-consent guidance after concerns that its previous wording implied that virtually any remuneration associated with research risk was unacceptable. OHRP clarified that although IRBs must not treat remuneration as offsetting risk when deciding whether research is approvable, remuneration to participants may include compensation associated with risks, and such compensation may be an acceptable reason for someone to participate.
This produces an important distinction:
IRB risk-benefit assessment
Payment should not be counted as a benefit that makes otherwise excessive research risk acceptable.
Participant's own decision
Under OHRP's interpretation, remuneration associated with risk may legitimately matter to an informed participant deciding whether acceptable research is worthwhile personally.
This difference between CIOMS and OHRP is substantive, not merely terminological. Researchers should therefore avoid presenting one universal rule about paying participants more for riskier research.
More Burdensome Does Not Necessarily Mean More Risky
This distinction is easy to lose in practice.
A study visit may become longer, more inconvenient, or more uncomfortable without materially increasing research risk. Conversely, a procedure can increase risk without greatly increasing time.
If researchers automatically increase payment whenever "risk" seems greater, they may actually be compensating for additional time, discomfort, effort, or inconvenience without realizing it.
A better payment rationale names the relevant factor precisely.
There Is No Universal Formula
No major authority reviewed here prescribes a general equation such as:
The absence of a formula is not a defect. Ethical payment involves judgments about fairness, context, participant burden, local monetary value, institutional policy, and the applicable regulatory or ethical framework.
04 · A Practical Example
Three Study Visits That All Last Two Hours
Hypothetical Example
Same Time, Different Participant Experiences
A research team is designing compensation for three hypothetical two-hour study visits. The duration is identical, but what participants experience is not.
Visit A: Two-hour interview
The participant spends two hours answering questions in a comfortable setting with minimal additional burden.
Payment consideration
Time provides a clear basis for compensation, with any travel expenses considered separately for reimbursement.
Visit B: Two-hour demanding procedure
The participant spends the same amount of time but must fast beforehand, follow inconvenient preparation instructions, and undergo an uncomfortable procedure.
Payment consideration
The rationale may appropriately consider additional inconvenience, effort, burden, or discomfort rather than pretending that equal duration makes the visits equivalent.
Visit C: Procedure involving greater research risk
The participant again spends two hours, but the procedure introduces greater risk while not substantially increasing time or inconvenience.
Payment consideration
The ethics committee must first determine that the risk is acceptable independently of payment. Whether risk itself should then affect compensation depends on the governing ethical framework rather than a universal rule.
The comparison shows why payment design benefits from separating the dimensions of participation. "Two hours" is useful information, but it is not a complete description of what the participant is being asked to undertake.
07 · A Quick Checklist
Before Basing Participant Payment on Time, Inconvenience, or Risk
For each proposed payment, check:
Estimate the actual time required for study activities and relevant travel rather than only the duration of the primary procedure.
Identify inconvenience, effort, burden, and discomfort that elapsed time alone does not capture.
Separate direct expenses that may warrant reimbursement from compensable time and inconvenience.
Avoid automatically treating discomfort, inconvenience, and research risk as equivalent concepts.
Verify whether the ethical framework governing the study permits risk itself to influence compensation.
Ensure that research risk is ethically acceptable independently of any participant payment.
Document why different procedures, visits, or participant activities receive different compensation when applicable.
Submit the amount, purpose, method, and schedule of payment for required ethics review.
