Causation in Canada revisited: material contribution to risk and the impact of Clements (Litigation Guardian of) v. Clements.

AuthorGalway, Samantha

Samantha Galway is a second year law student at Queen's University in Kingston, Ontario. She prepared an earlier version of this paper for her first year Torts Class, in which she received the Fasken Martineau DuMoulin LLP Prize in Torts, awarded on the basis of academic excellence. Gord McKee is a senior litigation partner at Blake, Casseis & Graydon LLP, whose practices focuses on product liability and class action defence. He was co-author on an earlier article published in the Defense Counsel Journal discussing causation law in Canada. (1)

AT least until 2012, there was significant confusion in Canadian jurisprudence surrounding one aspect of the standard for causation in negligence actions. Canadian courts referred to this aspect as the "material contribution" test. In some of its articulations of this test, the courts were talking about a concept similar to the U.S. "substantial contributing factor" test. But in others, they seemed to be talking about something very different. The Supreme Court of Canada had been criticized by academic commentators for its failed attempts, in its earlier decisions in cases such as Athey v. Leonati (3) and Hanke v. Resurfice Corp. (4), to clarify the law in this area. Some critics, including one of the authors of this paper, argued that these decisions only served to further complicate an already unclear area of Canadian tort law. (5) In 2012, the Supreme Court addressed the issues raised in a number of these criticisms, and substantially clarified the law, drawing a clear distinction between two more precisely worded concepts --"material contribution to injury" and "material contribution to risk". (6) The former concept is nothing new or surprising, and akin to "substantial contributing factor". The same cannot be said for the latter, however.

This paper will examine in more detail the 2012 decision of the Supreme Court of Canada in Clements (Litigation Guardian of) v. Clements, (7) and the Court's guidance regarding the material contribution to risk test. While the material contribution to risk test is now clearly part of Canadian tort law, it is a doctrine that will only rarely come into play. For this reason, the test has been referred to as the "unicorn" of Canadian law, often talked about but rarely seen. (8) Given the right fact pattern, this doctrine may be available to assist a plaintiff to establish liability in a negligence action where "but for" causation cannot be established, with or without application of the material contribution to injury test.

  1. "But for'" Is Still the Default Test for Causation

    Causation is one of the requisite elements that must be established to bring an action in negligence. It is required in order to link the harm inflicted on the plaintiff to the breach of duty owed by the tortfeasor. (9) To allow recovery where an injury would have occurred absent any breach of duty on the defendant's part would neither further the goals of compensation, fairness and deterrence, nor comport with the theory of corrective justice that underlies the law of negligence. (10)

    The fundamental rule for determining causation in Canada continues to be the "but for" test. (11) The plaintiff must establish that but for the defendant's negligent conduct (falling below the applicable standard of care) the plaintiff would not have experienced the injury. (12) The defendant's conduct does not have to be the sole cause or even the most important. It just has to have been a materially contributing factor--a necessary ingredient--in the occurrence of the injury. Establishing this connection is a "factual inquiry". (13) Plaintiffs must establish "but for" causation on a balance of probabilities in order to succeed in their claim.

    The Supreme Court of Canada in Clements reaffirmed that the court's go-to tool for determining causation remains the "but for" test. However, the Court in Clements also acknowledged that there are circumstances where it may be impossible for a plaintiff, through no fault of his or her own, to prove causation. Recognizing that "but for" may "offend basic notions of fairness and justice" in some circumstances, the Court in Clements went on to discuss and clarify when a plaintiff might seek to invoke the material contribution to risk test.

  2. Clarifying "Material Contribution to Injury" vs. "Material Contribution to Risk"

    One issue that arises when attempting to track the evolution of causation through Canadian jurisprudence is the ambiguous use of the term "materially contributed". As stated by Lord Reid in McGhee v. National Coal Board, (14) "a [claimant] succeeds if he can [show] that fault of the defender caused or materially contributed to his injury." The Supreme Court of Canada endorsed this principle in both Snell v. Farrell and Athey v. Leonati. (16) The "material contribution" that Lord Reid refers to in McGhee, and that the Supreme Court of Canada appears to be referring to in Athey, (17) is a material contribution to the injury.

    In Snell, Sopinka J. referenced Lord Bridge's decision in Wilsher v. Essex Area Health Authority, (18) in which he held that if a "robust and pragmatic" approach is applied to the facts, it is possible for the Court to legitimately infer that the defendant's negligence materially contributed to the plaintijfs injury even though medical or scientific expertise cannot arrive at a definitive conclusion. (19) Where the defendant's act materially contributed to was a "necessary ingredient" in the occurrence of--the injury, it is no different, in effect, from saying that "but for" that act or...

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