How does mitigation work in a personal injury action?

The burden of proof on the issue of mitigation lies with the defence. As stated by Rowles J.A., writing for the majority, in Graham v. Rogers, 2001 BCCA 432, at para. 35, regarding the principle of mitigation in personal injury cases: Mitigation goes to limit recovery based on an unreasonable failure of the injured party to take reasonable steps to limit his or her loss. A plaintiff in a personal injury action has a positive duty to mitigate but if a defendant’s position is that a plaintiff could reasonably have avoided some part of the loss, the defendant bears the onus of proof on that issue.

This principle has been applied to arguments that a plaintiff has not pursued a course of recommended medical treatment. In Chiu v. Chiu, 2002 BCCA 618, Low J.A. wrote as follows at para. 57: … the defendant must prove two things: (1) that the plaintiff acted unreasonably in eschewing the recommended treatment, and (2) the extent, if any, to which the plaintiff’s damages would have been reduced had he acted reasonably.

The court is slow to determine that good faith decisions are unreasonable. As set out in Paniccia Estate v. Toal, 2012 ABCA 397, at para. 86: …the court only lightly reviews the decision of the person injured to try to mitigate his loss. Courts are extremely slow to criticize good-faith decisions by victims of torts about both whether to take steps in mitigation, or which steps, or how much expense or risk to incur in doing so.