Clinical background is not required for all functional roles in a clinical study as stated by many in previous posts, although I think it is critical to have experts with clinical background in the study depending on the type of device/ combination product being studied. For example, a study in which the objective is to evaluate an implant will definitely require physician(s) trained and qualified to perform implantation and removal procedures. 21 CFR 812.43(a) states “A sponsor shall select investigators qualified by training and experience to investigate the device.” An investigator does not need to be a medical doctor. A physician can be a subinvestigator to perform those study functions requiring the appropriate level of medical expertise.