Payment for participating in medical research may be coercive without necessarily undermining a participant’s consent, according to an article published in The American Journal of Bioethics.

Offering payment to someone to participate in a study does not constitute a threat or a violation of rights but it may be considered coercion as subjection if the participants feel they must participate because of poverty, because payment reinforces the study as the only means of avoiding continued poverty, or because the researchers’ and participant’s motivations for enrollment do not align.

Although such a payment is not likely to make participation involuntary or invalid, it creates a potential setback to the interests of the participant. To avoid this scenario, the authors propose 3 strategies.

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  • Acceptable alternatives: enrollment is performed in an area where acceptable alternatives to research participation are likely to be available to applicants.
  • Shared goals: enrollment is performed in an area where potential participants are likely to be motivated by goals similar to those of the researchers.
  • Ample benefits: participants are provided with greater benefits to offset the harm of coercion.

The authors conclude that “the size of the payment does not matter to whether an agreement is coercive.” For example, if refusing payment will not leave the participant in a negative situation, even high payment amounts are not coercive. According to the researchers, although consent-undermining coercion is always wrong, coercion as subjection may not be wrong if it is acceptably balanced with other positive and negative aspects of study participation. The aforementioned alternative strategies offer potential ethical solutions if coercion by subjection is identified by a research ethics committee.


Millum J, Garnett M. How payment for research participation can be coercive. Am J Bioeth. 2019;19(9):2131.