Canada: Causation, Causation, Causation — Is What's Old New Again Or Are Times A "Changing"

First presented at the CDL Fall Classic.


"Study the past if you would define the future" - Confucius

Just as Confucius guided us so many centuries ago, similarly, in order to understand the concept of causation in accident benefits context, we must look to the past.

The year is 2008. The case of Monks v. ING Insurance1 had now reached Justices Cronk, Gillese and Watt of the Court of Appeal for Ontario. Justice Cronk writing for the unanimous Court summarized the jurisprudence on causation in accident benefits matters to that date:

[85] Athey v. Leonati2 is the leading Canadian case on causation in tort law. In Athey, Major J. reiterated the following well-established principles:

(1) The general, but not conclusive, test for proof of causation is the "but for" test, which requires a plaintiff to show that his or her injury would not have occurred but for the negligence of the defendant (paragraph 14).

(2) In certain circumstances, where the "but for" test is un-workable, causation may also be established where it is demonstrated that the defendant's negligence "materially contributed" to the occurrence of the tort victim's injury. It is not necessary for the plaintiff to establish that the defendant's negligence was the sole cause of the injury (paragraphs 15 and 17).

(3) Liability will be imposed on a defendant for injuries caused or materially contributed to by his or her negligence. That liability is not reduced by the existence of other nontortious contributing causes (paragraphs 22 and 23).

Although tort law clearly limited the use of the "material contribution" test, the accident benefits jurisprudence continued to use it in many instances as the appropriate test for causation. In Monks, Cronk J.A. stated:

More recently, in Resurfice Corpo. v. Hanke3 ... the Supreme Court of Canada clarified the exception to the "but for" causation test and the circumstances in which the material contribution test may be applied. I do not understand Resurfice to alter the basic causation principles that I have described.

Since 2009, both the Court of Appeal and the Supreme Court of Canada indirectly raised scepticism about the jurisprudence supporting the "material contribution" test as the default test in accident benefits matters.

In Clements (Litigation Guardian of) v. Clements,4 Chief Justice McLachlin stated the following:

The legal issue is whether the usual "but for" test for causation in a negligence action applies, as the Court of Appeal held, or whether a material contribution approach suffices, as the trial judge held. For the reasons that follow, I conclude that a material contribution test was not applicable in this case. I would return the matter to the trial judge to be dealt with on the correct basis of "but for" causation.5

As for the "material contribution" test, the Chief Justice McLachlin observed:

The idea running through the jurisprudence that to apply the material contribution approach it must be "impossible" for the plaintiff to prove that the defendant's negligence caused the plaintiff's injury using the "but for" test has produced uncertainty in this case and elsewhere.6

Finally, in Blake v. Dominion of Canada General Insurance Co.7 Brown J.A. applied the "but for" test in an accident benefits case. He reasoned his decision based on the fact that the plaintiff counsel did not ask the trial judge to depart from the general "but for" test of causation. In other words, Brown J.A. implied that, without specific request and justification, the "but for" test remained the default test in accident benefits matters as it continued to be in the tort context.

The "But-For" Test

It is a basic principle of the law of negligence that it is not sufficient for a plaintiff to merely demonstrate that a defendant had acted negligently; it must also establish that the defendant's negligence is what caused the plaintiff's injury.8 The onus lies on the plaintiff to establish causation as a probability and it is insufficient to merely demonstrate that the defendant's negligence caused the plaintiff injury.9 The proof of causation is a necessary element of negligence, as "a defendant in an action in negligence is not a wrongdoer at large: he [or she] is a wrongdoer only in respect of the damage which he [or she] actually causes to the plaintiff."10

The test for establishing causation is the "but for" test, which requires the plaintiff to prove on the balance of probabilities that the defendant's negligence was necessary to bring about the injury.11 The "but-for" test has almost universal acceptance as an instrument for ascertaining causation. The formula postulates that the defendant's fault is a cause of the plaintiff's harm if such harm would not have occurred without (but for) it.12

The "Material Contribution" Test

As outlined in Clements, the basic rule of recovery for negligence is that the plaintiff must establish on a balance of probabilities that the defendant caused the plaintiff's injury on the "but for" test. However, there are certain rare instances when the plaintiff might be entitled to recovery for negligence on the basis of "material contribution" test. This can occur in cases where it is impossible to determine which of a number of negligent acts by multiple actors caused the injury, but it is established that one or more of them did in fact cause it. In these rare instances, the underlying public policy initiatives prohibit the defendant from escaping liability by shifting the blame at another wrongdoer. Therefore, Courts allowed for the defendant to be found liable on the basis that he or she materially contributed to the risk of the injury.

As set out by Smith J.A. in MacDonald (Litigation Guardian of) v. Goertz13

... "material contribution" does not signify a test of causation at all; rather it is a policy driven rule of law designed to permit plaintiffs to recover in such cases despite their failure to prove causation. In such cases, plaintiffs are permitted to "jump the evidentiary gap"... That is because to deny liability "would offend basic notions of fairness and justice".14

However, in accident benefits context "material contribution" test has taken on a different meaning then in tort law. As explained by Director's Delegate Evans, the use of the "material contribution" test has caused confusion at the Financial Services Commission of Ontario ("FSCO") because:

[material contribution] has a specific meaning in tort cases, as set out in Resurfice, but in cases at the Commission it means that a cause of the disability — injuries arising from a motor vehicle accident — is materially contributing to the disability despite other causes, whether they arose before or after the accident.15

Therefore, it is important to note that the "material contribution" test is not the default test for proving causation in accident benefits context and it should only be utilized where it is impossible to determine which of a number of negligent acts by multiple actors caused the injury.

Mere Temporal Relationship ≠ Causation

The Courts have urged against making inferences of causation based on a mere presence of temporal relationship. In other words, where causation is supported by the fact that an injury appeared or worsened after the accident, there should be close scrutiny of all the evidence available and the inference that causation is satisfied should not be drawn from the temporal relationship. The decisions below shed further light at the dichotomy between causation and temporal relationship and caution against inferring causation from a mere presence of temporal relationship.

In White v Stonestreet,16 a plaintiff was involved in a motor vehicle accident. However, the plaintiff had a pre-existing degenerative condition and the Court cautioned against inferring a causal connection from a temporal one. The plaintiff's experts claimed that since the plaintiff did not have lower back pain before the accident but developed lower back pain after the accident, the accident must have been the cause. The Court rejected this claim.

Furthermore, in Rollins v. English Language Separate District School Board,17 the plaintiff was a six year old girl who was struck in the head by swinging rollerblades in the schoolyard. Later that evening, the plaintiff became sick and her eye was twitching. She went into convulsions the following day and was eventually diagnosed with Rasmussen's encephalitis.

The plaintiff's doctor theorized that the blow to the head by the swinging rollerblades caused blood brain barrier long enough to allow antibodies to cross over and attack her brain. As a result, the plaintiff brought an action against the school board and the principal for breaching their duties of care. However, the Court held that there was no reliable scientific evidence to conclude that mild brain trauma was causative factor in onset of Rasmussen's encephalitis. Further, the Court held that there was no reliable evidence upon which it could draw an inference that the blow to the head by swinging rollerblades resulted in Rasmussen's encephalitis. In other words, the Court refused to infer a causal connection from a temporal one.

Current State of Law

The current state of Canadian law involving the proof of causation is twofold. The plaintiff can prove causation by proving that he or she would not have suffered the loss through the "but for" test. In the alternative and in rare and exceptional circumstance, a plaintiff may prove causation by indicating that the defendant's conduct was "material contribution" to risk of the plaintiff's injury. Furthermore, in order to successfully utilize the "material contribution" test, the plaintiff must establish both of the following criteria:

(i) the plaintiff must establish that his or her loss would not have occurred "but for" the negligence of two or more tortfeasors; and

(ii) the plaintiff, through no fault of his or her own is unable to show that any one of the possible tortfeasors in fact was the necessary or "but for" cause of her injury.

In addition, proof of causation in accident benefits cases has been reconciled in Kofi Agyapong v. Jevco Insurance Company.18 In Agyapong, the issues were whether the Applicant was entitled to non-earner, and housekeeping and home maintenance benefits as a result of a motor vehicle accident in which he was struck by a pickup truck as a pedestrian. The Applicant had preexisting impairments including an industrial accident, a criminal assault, and two previous motor vehicle accidents.

Arbitrator John Wilson held that the Applicant did not meet the evidentiary burden of proving his entitlement to non-earner, and housekeeping and home maintenance benefits. More importantly, Arbitrator Wilson reviewed both the Supreme Court of Canada's decision in Clements and the Court of Appeal's decision in Blake and subsequently concluded that the "but for" test is not only the default test for proving causation in tort law but also in accident benefits cases, as well.

More recently, in Ms. K and State Farm Mutual Automobile Insurance Company, Arbitrator Feldman confirmed that the "primary test for causation in an accident benefits case remains the "but for" test" and that the "material contribution" test is only to be used where the "but for" test's application is impossible.19 This decision further supports the underlying conclusion that the "but for" test is to be the default test to prove causation in the accident benefits cases.


Through its lengthy history, the "but-for" test has proven to be worthy of its title as the default test for ascertaining causation. In proving causation, the "but-for" test is the default test in tort as well as in accident benefits cases and "material contribution" test is virtually non-existent. In the words of Arbitrator Wilson from Agyapong, "the days of the ritual application of the "material contribution" approach in accident benefit matters are numbered at best..."20


1 Monks v ING Insurance Co of Canada, [2008] 90 OR (3d) 689 (Ont. CA).

2 Athey v Leonati, [1996] CarswellBC 2295 (SCC).

3 Resurfice Corpo v Hanke, [2007] 1 SCR 333

4 Clements (Litigation Guardian of) v Clements, [2012] 2 SCR 181.

5 Supra at para 5.

6 Supra at para 35.

7 Blake v Dominion of Canada General Insurance Co, [2015] OJ No 1218 (Ont. CA).

8 Clements at para 6.

9 Rothwell v Raes, 1988 CarswellOnt 1085, paras 245 and 246; see also Edgar v. Richmond (Township), 1991 CarswellBC 800, at Para. 107

10 Mooney v. British Columbia (Attorney General), 2004 BCCA 402 (CanLII), 202 B.C.A.C. 74, at para. 157, affirmed by the Supreme Court of Canada in Clements v. Clements, [2012] 2 SCR 181, Para. 16.

11 Clements at para 8, 9 and 10.

12 March v Stramare [1991] 171 CLR 506.

13 MacDonald (Litigation Guardian of) v Goertz, [2009] 275 BCAC 68 (BCCA).

14 Supra at para 25.

15 Arunasalam v State Farm Mutual Automobile Insurance Co., [2011] O.F.S.C.D. No. 21, at para. 30.

16 White v Stonestreet, [2006] B.C.J. No. 1150 at paras 70, 71, 74 and 75.

17 Rollins (Litigation guardian of) v. English Language Separate District School Board No. 39, [2009] O.J. No. 6193.

18 Kofi Agyapong v. Jevco Insurance Company, FSCO A11-003445.

19 Ms. K and State Farm Mutual Automobile Insurance Company [2016] O.F.S.C.D. No. 127 at para. 25.

20 Agyapong, at paras. 64 and 65.

The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.

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