Physician-researchers are bound by professional obligations stemming from both the role of the physician and the role of the researcher. Currently, the dominant models for understanding the relationship between physician-researchers' clinical duties and research duties fit into three categories: the similarity position, the difference position and the middle ground. The law may be said to offer a fourth.

In the research ethics literature, there is strong disagreement about the ethical acceptability of placebo-controlled trials, particularly when a tested therapy aims to alleviate a condition for which standard treatment exists. Recently, this disagreement has given rise to debate over the moral appropriateness of the principle of clinical equipoise for medical research. Underlying these debates are two fundamentally different visions of the moral obligations that investigators owe their subjects.Some commentators and ethics documents claim that physicians, whether acting as care givers (...) or researchers, have the same duty of beneficence towards their patients and subjects: namely, that they must provide optimal medical care. In discussing placebo surgery in research on refractory Parkinson's disease, Peter Clark succinctly states this view: “The researcher has an ethical responsibility to act in the best interest of subjects.”. (shrink)