This thesis addresses the tension in pragmatic cluster-randomized trials between their social value and the requirement to respect the autonomy of research participants. Pragmatic trials are designed to evaluate the effectiveness of treatments in real-world settings to inform clinical decision-making and promote cost-efficient care. These trials are often embedded into clinical settings and ideally include all patients who would receive the treatments under investigation as a part of routine care. Trialists increasingly adopt cluster-randomized designs—in which intact groups, such as hospitals (...) or clinics, are allocated randomly to study interventions—to simplify the inclusion of all patients. But including all-comers conflicts with the requirement to obtain written informed consent from research participants. Since informed consent is central to respecting patient autonomy, the question arises: how can the ends of autonomy and pragmatism be served simultaneously? Some philosophers argue that patients have an obligation to participate in clinical research and that this may negate consent requirements. I argue that while there may be grounds for a prima facie obligation for patients to participate in clinical research, no compelling argument has demonstrated that the obligation is enforceable. Others assert that broad application of a waiver of consent will facilitate the conduct of pragmatic cluster-randomized trials. I demonstrate that this proposal sharply conflicts with the historical origins of the waiver. I articulate a novel moral foundation for the use of a waiver of consent and show that when trials evaluate treatments delivered directly to patients, the autonomy interests at stake for participants are too substantial to permit its use. My solution draws a distinction between consent requirements in existing policy and consent as an autonomous authorization. As many pragmatic cluster-randomized trials are conducted in primary care settings with no research staff, I argue that patient autonomy can be promoted and protected using clinical-style consent, in which health providers seek verbal informed consent from patients and document it in the electronic health record. This approach has been associated with high rates of recruitment and, thus, may satisfy both requirements for social value and respect for autonomy. (shrink)