I may be overthinking this. Is a letter of recommendation that is cosigned by a physician and by your supervisor, still considered an official letter of recc from a physician? Context: I have worked alongside my supervisor and the physician, but am closest to the supervisor. Would it better to have the letter be cosigned by both or solely signed by the physician. The physician wrote: "Given how closely you worked with him, it might be best to have him draft a letter outlining your strengths and I could either sign that or cosign it (sometimes they look at how closely the writer knows the applicant, how much time they spent together, etc. ) Whatever you think is best."