The Test to Determine Causation
[31] Both the Arbitrator and the Director’s Delegate looked to the jurisprudence of the courts to determine the appropriate test for causation. The decisions of the Supreme Court of Canada in Clements v. Clements, above, Athey v. Leonati, above and Resurfice Corp. v. Hanke, 2007 SCC 7 (CanLII), [2007] 1 S.C.R. 333 provide guidance in determining causation in a personal injury case. The Ontario Court of Appeal in Monks v. ING, above, held that the same analysis applies in the accident benefit context: see Monks at paragraphs 88 and 89. That analysis is as follows:
a. Causation is a factual determination made on a balance of probabilities: Clements at paragraph 46;
b. The test for establishing causation is the “but for” test;
c. The Supreme Court in Clements held that, “As a general rule, a plaintiff cannot succeed unless she shows as a matter of fact that she would not have suffered the loss “but for” the negligent act or acts of the defendant. A trial judge is to take a robust and pragmatic approach to determining if a plaintiff has established that the defendant’s negligence caused her loss. Scientific proof of causation is not required.” See Clements at paragraph 46;
d. “There is no indication in the SABS of a legislative intent that an insurer’s liability for the accident benefits in issue in this case should be subject to discount for apportionment of causation due to an insured’s pre-existing injuries … The SABS simply states, in clear and unambiguous language, that an insurer ‘shall pay an insured person who sustains an impairment as a result of an accident, medical, rehabilitation and attendant care benefits.’”: See Monks at paragraphs 94 to 96;
e. In exceptional circumstances, where (i) the plaintiff establishes that her loss would not have occurred “but for” the negligence of two or more tortfeasors, each of whom could be responsible for the loss; but (ii) the plaintiff is unable through no fault of her own, to show that one tortfeasor is the “but for” cause of her injuries because each tortfeasor can point to the other as the possible “but for” cause of the injury, a plaintiff may establish liability against one defendant if that defendant’s conduct materially contributed to the plaintiff’s risk of injury: See Clements at paragraph 46;
f. This is because public policy dictates that a defendant should not be permitted to escape liability by pointing the finger at another wrongdoer, thereby defeating a finding of causation on a balance of probabilities against anyone: See Clements at paragraphs 13 and 46;
g. A material contribution to the risk of impairment is one that falls outside the de minimis range: See Athey at paragraph 44.”