Compensation in clinical trials

Last update: 28 October 2015

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Although not always a standard, in many clinical trials participants receive some form of compensation for their participation. This may take the form of money, or the reimbursement of travel expenses, food or food vouchers, or other services. The following article provides more information on the topics of compensation and reimbursement and their associated issues.

What is reimbursement in clinical trials?

Reimbursement expenses refer to any expenses incurred in relation to participation in a clinical trial. Reimbursement is payable to all eligible participants or their legally designated representatives. This is documented before a clinical trial begins.

For example, reimbursement may cover:

  • Travel expenses
  • Accommodation
  • Loss of income
  • Meals

What is compensation in clinical trials?

Compensation in clinical trials can mean two distinct things:

  • When participants receive monetary or other benefits for their participation in the clinical trial; or
  • If participants receive a payment or other services when they suffer any harm from a clinical trial.

Compensation is more common in Phase I trials with healthy volunteers, and is usually paid to participants in recognition of their time sacrifice and as appreciation of their contribution for science.

Compensation for participation

Whether or not compensation is paid to participants depends on the sponsor and the given study. Many clinical research organisations (CROs) even advertise participation in clinical studies as it offers a (limited) possibility to earn money. This practice is particularly common in the United States where the National Institutes of Health even have a standard tariff for participation.

The legislation and practice regarding compensation in Europe vary widely. Some countries exclude compensation entirely, but the most common practice requires that any compensation is reviewed and approved by the respective Ethics Committee. According to the EU Clinical Trial Directive (2001/20/EC)1 and Regulation (536/2014)2, no incentives or financial inducements are given to incapacitated participants or minors (or either of their legally designated representatives), or to pregnant women, except for compensation for expenses and loss of earnings directly related to participation in the clinical trial. Otherwise, this EU legislation dictates that ‘no undue influence, including that of a financial nature, [must be] exerted on subjects to participate in the clinical trial.’

Compensation for harm suffered (insurance)

The EU Clinical Trials Directive introduced an ‘obligatory insurance/indemnity’. The regulation recognises that clinical trials do not always pose additional risk to the participants over normal clinical treatment. Therefore in such cases of no additional risk, or of negligible risk, no specific damage compensation (insurance or indemnity) will be required. With respect to trials where there is additional risk and the sponsor is obliged to ensure adequate insurance coverage, the Regulation puts EU Member States under an obligation to set up a national indemnification mechanism on a not-for-profit basis. The EU also requires all sponsors and CROs to be completely transparent about financial transactions made with participants or trial sites.

The Informed Consent Form (ICF) signed by the participant must contain specific references to any compensation schemes, and the insurance coverage offered to the participants should they suffer any injury or harm. The ICF should also be specific about how the insurer can be contacted, so that patients are not necessarily required to arrange their claims through the study personnel or the CRO.

Ethical considerations

Payments in clinical trials have raised ethical concerns for many years. The concerns focus on whether the payments are coercive or induce participants to take part in clinical research. This is an ongoing debate.

Vulnerable populations

Compensation is always a special concern with vulnerable populations, particularly in children and people with intellectual or mental disabilities. People in these vulnerable populations do not or cannot make their own decisions, so their parents/legal guardians decide for them, but the risk is not always divided in the same way. The member of the vulnerable population carries the risk, but the parent or guardian gets the compensation. This is one of the reasons why the EU does not allow compensation to such vulnerable populations or their legal guardians beyond the reimbursement of their expenses. Patient advocates and patient organisations may play a key role in mediating these situations, and flagging any irregular practices in this field to the authorities.

How much compensation?

There are various models that help set the amount of compensation that participants may receive for taking part in a trial. The table below explains the most common models, as presented in Pandya and Desai (2013).3


Table listing the different types of compensation models
Model Guiding principle Description Advantages Disadvantages
Market model Supply and demand – Compensation given in studies that offer little-to-no benefits or with difficult-to-reach target populations; no compensation in studies that offer benefits or have a large target population – Easier to achieve target recruitment numbers

– Less financial sacrifice by subjects

– High completion rates

– Can lead to high compensation rates in studies where subjects are difficult to find.

– High compensation may serve as undue inducement to participate.

– High compensation can lead to subjects neglecting the risks associated with participation, or may lead subjects to hide important data that might make them ineligible for the study.

– May create a situation of competition for subjects between investigators involving payment amounts.

Wage model Egalitarianism – Subjects that are involved with similar activities should be paid similarly

– Recognises that participation in research requires little or no skill but does involve time, effort, and discomfort by the subject. Subjects thus paid on a scale parallel with that of unskilled but essential jobs

– Minimises issue of undue inducement

– Reduces inter-study competition

– Decreases financial sacrifice by the subject

– Prevents discrimination between high- and low-income groups

– Can create difficulties achieving target recruitment numbers

– Usually attracts low-income population

– Seen by some as an inappropriate commercialisation of research participation

Reimbursement model Egalitarianism – Compensation should cover only those costs incurred by the subject for participating in the trial

– Time spent away from work may be reimbursed in proportion to the subject’s earning capacity

– Minimises issue of undue inducement

– Subjects are less likely to hide information

– Subjects are less likely to overlook risks involved in participation

– Decreases financial sacrifice

– Possible difficulty achieving target recruitment numbers

– Possible preference of low-income group due to high study costs incurred by selecting the high-income group

Appreciation model – Compensation to come at the time of study completion as a token of gratitude – No real impact on study recruitment – May have an impact on subject retention, might act as inducement to prevent a patient discontinuing participation

– Needs to be used along with one of the other models

Table adapted from Pandya, M. & Desai, C. (2013). ‘Compensation in clinical research: The debate continues’. Perspectives in Clinical Research, 4(1), 70-74. Retrieved 28 August, 2015, from


  1. European Parliament (2001). Directive 2001/20/EC on the approximation of the laws, regulations, and administrative provisions of the Member States relating to the implementation of good clinical practice in the conduct of clinical trials on medicinal products for human use. Retrieved 8 October, 2015, from
  2. European Parliament (2014). Regulation (EU) No 536/2014 on clinical trials on medicinal products for human use, and repealing Directive 2001/20/EC. Retrieved 8 October, 2015, from
  3. Pandya, M. & Desai, C. (2013). ‘Compensation in clinical research: The debate continues’. Perspectives in Clinical Research, 4(1), 70-74. Retrieved 28 August, 2015, from



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