When multiple parties contribute to a single harmful event, Canadian tort law must determine how to allocate responsibility among them. This final lesson in the course examines the doctrines of apportionment and contributory negligence, which govern how courts distribute liability when more than one person bears fault for an injury or loss. For business owners, sole proprietors, and non-profit operators, understanding these principles is essential because they affect both the amount a defendant might ultimately pay and the potential for recovery when pursuing claims against others who have caused harm to the organization.
The foundation of these doctrines rests on a fundamental principle of fairness: liability should correspond to fault. If three parties each contributed to causing an accident, it would be unjust to make one party bear the entire cost while the others escape without consequence. Equally, if an injured party's own carelessness contributed to their harm, it would be unfair to require a defendant to compensate fully for losses that the plaintiff could have prevented. Apportionment and contributory negligence address these concerns by allowing courts to divide responsibility proportionally based on each party's degree of fault.
Historically, the common law took a much harsher approach to these situations. Under the old doctrine of contributory negligence, any fault on the part of the plaintiff, no matter how small, completely barred recovery. A plaintiff who was even one percent responsible for their own injuries could recover nothing from a defendant who was ninety-nine percent at fault. This all-or-nothing approach produced harsh results and was eventually replaced by legislative reform across Canada. Every common law province has now enacted legislation establishing a system of comparative fault that permits apportionment of damages according to the degree of responsibility attributable to each party.