What is the difference between error in the exercise of clinical judgment and actionable negligence?

The law has long distinguished between errors in the exercise of clinical judgment and actionable negligence. In a retrospective analysis of the actions of doctors and nurses, one must be careful not to confuse the reasonable exercise of clinical judgment, which of course will vary from practitioner to practitioner, with the concept of the negligent performance of one's duties: Wilson v. Swanson, 1956 CanLII 1 (SCC), [1956] S.C.R. 804.

Even if a medical professional has breached the appropriate standard of care, the plaintiff must still establish that the breach is causally connected to the plaintiff's injury. The plaintiff must show that but for the defendant's breach the injury would not have occurred, or that the breach materially contributed to the occurrence of the injury: Athey v. Leonati, 1996 CanLII 183 (SCC), [1996] 3 S.C.R. 458. 2. Findings on Disputed Evidence