What is the burden of proving causation in medical malpractice cases?

In establishing causation in medical malpractice cases, the burden of proof lies with the plaintiff. The plaintiff must prove that the defendant’s breach of duty of care caused the injury. The plaintiff has the ultimate burden; however, where the defendant has failed to put forward evidence to the contrary, the courts may draw a “robust and pragmatic” inference of causation, based on the facts, that the defendant’s negligence materially contributed to the plaintiff’s injury, even though positive or scientific proof of causation has not been submitted: Snell v. Farrell (1990), 1990 CanLII 70 (SCC), 72 D.L.R. (4th) 289, [1990] 2 S.C.R. 311. The burden of proof does not shift to the defendant and the plaintiff remains fixed with the burden of proving causation on a balance of probabilities.