Causation in negligence -- a useful British Columbia decision

Ediger v. Johnston, 2011 BCCA 253 is a good source for the current law on causation. 

 

In this sad case a child was tragically injured during delivery.  The defendant obstetrician was negligent in failing to have a back-up surgical team “immediately available”. 

 

That said, the negligence was not the cause of the injury – the failure to have back-up team immediately available did not, in itself, lead to any harm.  Accordingly the negligence claim failed. 

 

The Court holds:

 

[67]         Causation in negligence is determined by the “but for” test. The test requires the plaintiff to prove, on a balance of probabilities, that “the injury would not have occurred but for the negligence of the defendant”: Athey v. Leonati, [1996] 3 S.C.R. 458 at para. 15.

 

[68]         There are two aspects to the causation inquiry. The first requires the plaintiff to identify the specific acts of negligence by the defendant that caused the specific harm to the plaintiff. This is sometimes referred to as the cause-in-fact (i.e., factual causation) of the plaintiff’s injuries and requires a substantial connection between the defendant’s negligent act and the harm to the plaintiff. The second aspect of the inquiry requires the plaintiff to establish the proximate cause between the defendant’s negligent conduct and the plaintiff’s loss or harm. This is sometimes referred to as the cause-in-law (i.e., legal causation) and requires the loss or harm caused by the negligent conduct to fall “within the range of that for which it is just to make the defendant responsible” (W.V.H. Rogers, Winfield and Jolowicz on Tort, 17th ed. (London: Sweet & Maxwell, 2006) at 6-1. And see: L.N. Klar, Tort Law, 4th ed. (Toronto: Thomson Carswell, 2008) at 428-429). Legal causation defines the limits of a defendant’s liability.

 

[69]         The interplay between factual and legal causation is described in Winfield and Jolowicz on Tort at 6-3:

 

... “Causation in Fact”, is concerned with a question which arises (at least in theory) in every case, that is to say, whether the defendant’s act (or omission) should be excluded from the events which contributed to the occurrence of the claimant’s loss. If it is so excluded, that is the end of the case, for if there is no connection between the defendant’s act and the loss there is no reason for a private law system of liability to operate with regard to him. ... If we conclude that it was, we move on to consider whether it was a sufficiently legally effective cause among the complex of other causes (and there may be many) to justify imposing tort liability on the defendant.

 

[70]         Thus, if the plaintiff cannot establish factual causation that ends the inquiry: without cause-in-fact, there can be no cause-in-law.

 

[71]         The “but for” test has given rise to two theories of causation. The strict theory of causation requires that the defendant’s negligent act must fall “within the risk” (in Winfield and Jolowicz on Tort it is described as “within the range”) or be the “real causa causans” of the plaintiff’s harm or loss. In other words, the loss or harm “must result from the type of risk to which plaintiffs expose themselves, not from a totally different hazard”: Allen M. Linden in Canadian Tort Law, 8th ed. (LexisNexis Butterworths, 2006) at 490.

 

[72]         The source of the less stringent theory of causation was McGhee v. National Coal Board, [1923] All E.R. 1008, 1 W.L.R. 1 (H.L.). In that case, the Court found that causation was established if the defendant’s negligent act merely created a risk of harm or a “mere causa sine qua non” without which the plaintiff would not have suffered his or her loss or harm. In other words, the plaintiff was only required to prove that his or her injuries fell within the ambit of the risk of harm created by the defendant’s negligent act.

 

[73]         While proof of causation in medical malpractice cases can be challenging, in Snell v. Farrell, [1990] 2 S.C.R. 311 the Supreme Court of Canada rejected the less stringent approach from McGhee and adopted the strict theory of causation. For the Court, Mr. Justice Sopinka reasoned as follows:

 

[26]      ... Is the requirement that the plaintiff prove that the defendant’s tortious conduct caused or contributed to the plaintiff’s injury too onerous? Is some lesser relationship sufficient to justify compensation? I have examined the alternatives arising out of the McGhee case. They were that the plaintiff simply prove that the defendant created a risk that the injury which occurred would occur. Or, what amounts to the same thing, that the defendant has the burden of disproving causation. If I were convinced that defendants who have a substantial connection to the injury were escaping liability because plaintiffs cannot prove causation under currently applied principles, I would not hesitate to adopt one of these alternatives. In my opinion, however, properly applied, the principles relating to causation are adequate to the task. Adoption of either of the proposed alternatives would have the effect of compensating plaintiffs where a substantial connection between the injury and the defendant’s conduct is absent.

 

[74]         In Snell, the plaintiff lost her eyesight after cataract surgery. An anaesthetizing injection caused bleeding behind the plaintiff’s eye. The ophthalmologist surgeon was found negligent in failing to detect the bleed during the surgery and discontinue the operation. There were two possible causes for the resulting atrophy to the optic nerve: the undetected bleed during the surgery or natural causes. Neither of the medical experts at trial could state with any certainty which of these events caused the injury to the optic nerve and consequential loss of the plaintiff’s eyesight.

 

[75]         The trial judge ruled out natural causes. He held that the defendant doctor’s negligence had increased the risk of damage to the plaintiff’s eye, and that the loss of the plaintiff’s eyesight fell within the scope of that risk (which utilized the now rejected test in McGhee). The decision was upheld on appeal. On further appeal to the Supreme Court, the decision was upheld, although the McGhee reasoning was rejected. Instead, the Court concluded that where the defendant was in a better position to observe and interpret what occurred, and it was impossible for anyone else to detect the precise cause of the injury, the plaintiff could rely on a common sense inference that the bleed during the surgery caused the injury.

 

[76]         The Supreme Court of Canada confirmed its adoption of the strict theory of causation in St-Jean v. Mercier, 2002 SCC 15, [2002] 1 S.C.R. 491. On the issue of the scope of the risk of harm necessary to find causation, the Court stated:

 

[116]    The Court of Appeal appropriately said that it is insufficient to show that the defendant created a risk of harm and that the harm subsequently occurred within the ambit of the risk created. To the extent that such a notion is a separate means of proof with a less stringent standard to satisfy, Snell, supra, and definitely [Laferriere v. Lawson, [1991] 1 S.C.R. 541] should have put an end to such attempts at circumventing the traditional rules of proof on the balance of probabilities.

 

[77]         More recently, in Resurfice Corp. v. Hanke, 2007 SCC 7, [2007] 1 S.C.R. 333, Chief Justice McLachlin, for the Court, explained the requirement of a substantial connection between the defendant’s negligent conduct and the plaintiff’s injuries in order to meet the burden of the “but for” test:

 

[23]      The “but for” test recognizes that compensation for negligent conduct should only be made “where a substantial connection between the injury and the defendant’s conduct” is present. It ensures that a defendant will not be held liable for the plaintiff’s injuries where they “may very well be due to factors unconnected to the defendant and not the fault of anyone”: Snell v. Farrell, at p. 327, per Sopinka J. [Emphasis added.]

 

[78]         In Resurface, the Court rejected the notion that the material contribution test could be a substitute for the “but for” test and reiterated the default test of cause-in-fact as set in Snell, Athey v. Leonati, [1996] 3 S.C.R. 458 at para. 14, Walker Estate v. York Finch General Hospital, [2001] 1 S.C.R. 647, 2001 SCC 23, at paras. 87-88, and Blackwater v. Plint, [2005] 3 S.C.R. 3, 2005 SCC 58 at para. 78 (para. 19). The Court restricted the material contribution test to those situations where it is impossible to determine which of the negligent acts of two or more defendants created an unreasonable risk of the type of injury that the plaintiff experienced (para. 27) or where the “but for” chain of causation is broken by the inability of the plaintiff to prove what a person in the causal chain would have done had the defendant not committed the negligent act or omission (para. 28).

 

[79]         In Athey, the Court observed that “the courts have recognized that causation is established where the defendant’s negligence ‘materially contributed’ to the occurrence of the injury” (para. 15). However, the phrase “material contribution” in this statement from Athey is not synonymous with the “material contribution test” referred to in Resurface. The distinction between the two was explained by Mr. Justice Smith, for the majority, in Sam v. Wilson, 2007 BCCA 622:

 

[109]    “Material contribution”, as that phrase was used in Athey v. Leonati, is synonymous with “substantial connection”, as that phrase was used by McLachlin C.J.C. above in Resurfice Corp. v. Hanke. This causal yardstick should not be confused with the “material contribution test”. As McLachlin C.J.C. explained in Resurfice Corp. v. Hanke, at paras 24-29, the “material contribution test” applies as an exception to the “but for” test of causation when it is impossible for the plaintiff to prove that the defendant’s negligent conduct caused the plaintiff’s injury using the “but for” test, where it is clear that the defendant breached a duty of care owed the plaintiff thereby exposing the plaintiff to an unreasonable risk of injury, and where the plaintiff’s injury falls within the ambit of the risk.

 

[80]         In this particular case, the material contribution test was not applicable because it was not impossible for the respondent to prove that the appellant’s negligent conduct caused Cassidy’s injuries. The “but for” test of causation required the respondent to establish, on a balance of probabilities, a substantial connection between the risk of harm caused by the appellant’s negligent acts (the breach of the “immediately available” standard of care and/or failure to obtain Mrs. Ediger’s informed consent) and the resulting injuries to the respondent. In other words, in order to succeed, the respondent had to demonstrate that Cassidy’s injuries fell within the type of risk to which Mrs. Ediger was exposed, i.e., the forceps procedure, and that the appellant’s negligent conduct was the cause-in-fact or a “real causa causans” of Cassidy’s injuries