What is the test for successful medical negligence claims?

To succeed in an action for medical negligence, the plaintiff bears the onus of proving, on a balance of probabilities, that the defendant breached the standard of care. Ordinarily, expert evidence is required to establish the standard of care and determine whether the standard of care has been met: It is generally accepted that when a doctor acts in accordance with a recognized and respectable practice of the profession, he or she will not be found to be negligent. This is because courts do not ordinarily have the expertise to tell professionals that they are not behaving appropriately in their field: ter Neuzen v. Korn, 1995 CanLII 72 (SCC), [1995] 3 S.C.R. 674 at para. 38.

While there may be accepted practices that are “fraught with obvious risks” such that the practice itself may be negligent, that is not the issue here: ter Neuzen v. Korn, 1995 CanLII 72 (SCC), [1995] 3 S.C.R. 674 at 697. Here, expert evidence demonstrating a breach of the standard of practice is required.

With respect to the standard of care for physicians, they must practice in accordance with the conduct of a prudent and diligent doctor in the same circumstances: In the case of a specialist, … the doctor’s behaviour must be assessed in light of the conduct of other ordinary specialists, who possess a reasonable level of knowledge, competence and skill expected of professionals in Canada, in that field: ter Neuzen v. Korn, 1995 CanLII 72 (SCC), [1995] 3 S.C.R. 674 at para. 33.