McGill Faculty of Law: Extra-Contractual Obligations/Torts: Prof. Lara Khoury, 2002-03/Summary by Derek McKee
prevented the injury. (Part of the reason this was unclear is that no hearing tests were in fact carried out, so there was no evidence!)
On what basis could the gentamycine be held to have caused the injury?
Chouinard JA (for the majority) found that the facts, when put together, seemed to indicate causation. (He used the words “reversal of the burden of proof” but what he did was presume causation.)
Beauregard JA (dissenting) reversed the burden of proof of causation, because the absence of tests had prevented Gburek from being able to prove causation.
Farrell v. Snell,  2 S.C.R. 311. (CB1p532)
Snell went blind in her right eye due to complications in a cataract-removal operation. Although it was unclear what had caused the blindness, the trial judge concluded, “I am of the opinion that the defendant’s actions caused the plaintiff’s injury and that the defendant has not satisfied the onus that shifted to him.”
Was reversal of the burden of proof of causation necessary in this case?
The SCC ruled that courts can infer causation in the face of scientific uncertainty, even if there is no positive evidence from experts.
Sopinka J. rejected Wilberforce’s approach in McGhee, but he didn’t necessarily reject all kinds of reversals.
3. loss of chance
This concept is derived from contractual cases.
In some cases, the plaintiff is unable to prove that the defendant’s fault caused a loss, because chances are >50% that the loss would have happened anyway. The balance of probabilities test would not be satisfied.
However, the plaintiff may have lost a significant chance of advantage or benefit, even if it was less than 50%. If damages are awarded for the loss of the chance itself, they should be awarded in proportion to the probability.
This avoids an all-or-nothing approach, and it’s another way of dealing with increased risk.
The argument can only be used where the loss of chance is the only injury: i.e., a missed opportunity for something positive to happen.
This argument is mainly relevant to medical cases.
There is a mountain of arguments against loss of chance.
When you increase fault, you increase risk: should you be able to recover in every case?
This argument was rejected in the medical context in Laferrière v. Lawson.
Laferrière v. Lawson,  1 S.C.R. 541. (CB1p539)
Dupuis died from breast cancer after Dr. Lawson failed to follow up on early signs. (Laferrière sued as executor to Lawson’s estate.) It seems, however, that Dupuis would have died anyway, so the cause of her death was cancer, not Lawson’s fault.
Could Dupuis’s estate be compensated for the loss of the small chance that she might have survived if properly diagnosed?
Loss of chance is not compensable; “it is at least necessary that such a probability, or here, at most, a small possibility, translate into a concrete benefit for the patient which she can be said to have lost as a result of the doctor’s fault.” However, damages were awarded for pain and suffering and diminished quality of life.