What is the burden of proving causation in a motor vehicle accident case?

While causation is a question of fact that should be approached with common sense and, as Sopinka J. held in Snell v. Farrell, in a “robust and pragmatic” manner,[27] the robust and pragmatic approach does not shift the burden of proof away from the plaintiff. Rather, the plaintiff must establish an evidentiary foundation for finding that there is a causal nexus between the plaintiff’s injury and the defendant’s conduct.

Indeed, in Aristorenas v. Comcare Health Services, our Court of Appeal held that the robust and pragmatic approach should not be used as a means of making findings of fact in the absence of evidence that the defendant’s negligence caused the plaintiff’s injury. The majority held: The “robust and pragmatic” approach is not a distinct test for causation but rather an approach to the analysis of the evidence said to demonstrate the necessary causal connection between the conduct and the injury. Importantly, a robust and pragmatic approach must be applied to evidence; it is not a substitute for evidence to show that the defendant’s negligent conduct caused the injury.[28]

As the Court of Appeal held in Rothwell v. Raes, the onus on the plaintiff is not discharged “simply by demonstrating that there is the possibility of some causal connection.”[29]