1. The opinions expressed are the author's own. They do not reflect any position or policy of the National Institutes of Health, Public Health Service, Department of Health and Human Services, or any of the authors affiliated organizations.

Most ethics committees which review research protocols insist that potential research participants reserve unconditional or absolute ‘right’ of withdrawal at any time and without giving any reason. In this paper, I examine what consent means for research participation and a sense of commitment in relation to this right to withdraw. I suggest that, once consent has been given (and here I am excluding incompetent minors and adults), participants should not necessarily have unconditional or absolute rights to withdraw.This does not imply (...) that that there should be a complete absence of rights, or, indeed, an abandonment of the right to withdraw. The point of this paper is to show that the supposed unconditional or absolute nature of these rights may be self‐defeating and so fail to respect the autonomy of participants. In addition, and on a more positive note, I suggest that, attaching certain conditions on the right to withdraw, may better respect the autonomy of these participants by underlining the idea that autonomy is more than mere whim or indifference to the fate of others. On the contrary, research staff are currently unable to ‘push’ participants, who may merely have logistical difficulties unrelated to the research itself, but who really want to stay the course, for fear of coercing them. Furthermore, researchers now try to ‘screen out’ people they think may be unreliable to protect the science of the study and so groups at risk of dropping out may be unfairly denied access to research treatments. I conclude that on‐going negotiation between the relevant parties could be on balance the only truly acceptable way forward but concede certain important limitations to take into account. (shrink)

Objectives: To determine the effects of risk and payment on subjects’ willingness to participate, and to examine how payment influences subjects’ potential behaviours and risk evaluations.Methods: A 3 × 3 , between subjects, completely randomised factorial design was used. Students enrolled at one of five US pharmacy schools read a recruitment notice and informed consent form for a hypothetical study, and completed a questionnaire. Risk level was manipulated using recruitment notices and informed consent documents from hypothetical biomedical research projects. Payment (...) levels were determined using the payment models evaluated by Dickert and Grady as a guide. Five dependent variables were assessed in the questionnaire: willingness to participate, willingness to participate with no payment, propensity to neglect to tell about restricted activities, propensity to neglect to tell about negative effects, and risk rating.Results: Monetary payment had positive effects on respondents’ willingness to participate in research, regardless of the level of risk. However, higher monetary payments did not appear to blind respondents to the risks of a study. Payment had some influence on respondents’ potential behaviours regarding concealing information about restricted activities. However, payment did not appear to have a significant effect on respondents’ propensity to neglect to tell researchers about negative effects.Conclusions: Monetary payments appear to do what they are intended to do: make subjects more willing to participate in research. Concerns about payments blinding subjects to risks could not be substantiated in the present study. However, the findings do raise other concerns—notably the potential for payments to diminish the integrity of a study’s findings. Future research is critical to make sound decisions about the payment of research subjects. (shrink)

Xenotransplantation pits clinical research ethics against public health needs because recipients must undergo long-term, perhaps life-long, surveillance for infectious diseases. This surveillance requirement is effectively an abrogation of the right to withdraw from a clinical trial. Ulysses contracts, which are advance directives for future care, may be an ethical mechanism by which to balance public health needs against limitation of individual rights.