Intended for healthcare professionals

Student Education

Paying research participants

BMJ 2008; 336 doi: (Published 01 March 2008) Cite this as: BMJ 2008;336:0803118
  1. Kathy Boutis, masters degree student, health research methodology,
  2. Donald J Willison, associate professor

Kathy Boutis and Donald J Willison say financial compensation is unavoidable, but how much should participants in clinical research get?

Clinical research would be impossible without the participation of willing human participants. But paying participants in clinical research is contested among investigators, members of research ethics boards, and ethicists. Some defend payments for participation as fair and appropriate, but others find them problematic and even offensive or unethical.1234

We summarise some of the ethical challenges in considering paying participants in clinical trials. We describe three models commonly proposed for compensation.5 And we recommend evidence based approaches for paying participants to help investigators ensure high standards of safety while maximising recruitment.

Ethical challenges

Altering risk perception

Central to the ethical challenges in financially compensating participants in research is that money may unduly induce people to take part.246 Although most people agree that paying participants is an inducement, the amount at which it becomes an “undue inducement” is debatable. Most decisions are susceptible to multiple influences, says Grady in the American Journal of Bioethics, and therefore monetary inducements are likely to be compatible with risk assessment and voluntary choice.1

To minimise the risk of payment creating undue inducement, Grady recommends that institutional review boards are required to review the amount, method, and timing of payment. Under these circumstances a person could be allowed the freedom to decide whether or not to participate in research after reading the purpose, risks, benefits, alternatives, and requirements of the study when asked for informed consent.1

Empirical evidence shows that higher payment motivates participation in studies, but common payments levels do not alter research participants' assessment of risk.78 If decisions to participate represent rational trade-offs, competent people are free to decide. …

View Full Text

Log in

Log in through your institution


* For online subscription