There is a broad range of entrustment relationships, of which fiduciary relationships are an important but extreme instance.
A legal name for this kind of intermediate, limited entrustment is bailment.
The partial and limited entrustment described in the law concerning bailment fits the situation of medical researchers.
The combination of authorization and vulnerability does not alone suffice to generate an entrustment obligation, however.
On our view, then, clinical researchers have limited entrustment responsibilities that emerge from three principal constitutive conditions: the permissions granted by subjects, their resulting vulnerability to researcher discretion, and this trio of generally applicable duties.
The answer to the first question fixes the scope of entrustment, while the answer to the second fixes the strength of the grounds for ascribing ancillary-care responsibilities.
Since medical researchers are not trustees, the entrustment responsibilities incumbent on them are limited in both scope and strength.
In a rough way, the initial scope of the entrustment involved in any given research project is set by the extent and nature of permissions that subjects grant researchers in the informed consent process: these are matters of public record and objective fact, not of psychology.
In the course of a trial, the scope of entrustment can be expanded if subjects implicitly grant and researchers implicitly accept additional permissions.
Consequently, even if we assume that a given sort of ancillary care falls within the scope of entrustment, whether there is a responsibility to provide it will depend on how strong the case is for offering it, judged on the basis of the researchers' duties of compassion, engagement, and gratitude.
The kind of subject vulnerability that lies at the core of the partial entrustment between researcher and subject stems from the fact that it will he affected by subjects' health how researchers exercise the discretion that subjects indirectly grant them.