What is the legal test for difference of opinion?

Differences of opinion are a common experience in the medical and other professions. Indeed, that is why patients are often encouraged to “get a second opinion”. In Lindsay v. Freeman, [1995] O.J. No. 541 (Ont. Gen. Div.)paras 18, 21 the court observed: [in] the realm of diagnosis and treatment there is ample scope for genuine difference of opinion and a physician is not negligent merely because his conclusion differs from that of other professionals. The true test for establishing negligence in a diagnosis or treatment on the part of a physician is whether he has been proved guilty of such failure as no doctor of ordinary skill would be guilty of if acting with ordinary care.

Further, as the court stated in Pittman Estate v. Bain, [1994] O.J. No. 463 (S.C.J.) at para. 258: Where the subject matter is one requiring expert knowledge of a specialized area, and qualified respected specialists cannot themselves reasonably agree on the appropriate conduct, common sense dictates that the court should not decide that one body of opinion is more persuasive than another. Where reasonably informed people disagree, one of them cannot be labeled negligent.