Causation and damage principles

Bibik v. 2014052 Ontario Ltd. (Deluxe Windows of Canada),  2012 ONCA 135 released today has a useful summary of the treatment of  causation and damage principles:

i)       Principles of causation

[26]         In Snell v. Farrell, [1990] 2 S.C.R. 311, at p. 326, Sopinka J. described causation as “an expression of the relationship that must be found to exist between the tortious act of the wrongdoer and the injury to the victim in order to justify compensation of the latter out of the pocket of the former.” The prevailing test for causation is the “but for” test: see Hanke v. Resurfice, 2007 SCC 7, [2007] 1 S.C.R. 333.  It requires the trier of fact to conclude that “but for” the defendant’s misconduct, the plaintiff would not have suffered the injuries in question.

[27]         In rare cases, causation may also be proven on the basis of the material contribution test.  However, the test is only available where two stringent preconditions are met: (1) it must be “impossible” to prove causation using the “but for” test due to factors beyond the plaintiff’s control; and (2) the plaintiff’s injury must be within the ambit of risk created by the defendant’s breach: Hanke, at para. 25.  If, and only if, these two conditions are met, causation may be established by demonstrating that the defendant’s conduct was a material contributing cause of the plaintiff’s injury, that is, causation may be established on the basis of the material contribution test.

[28]         In this case the defendant conceded that the sexual assaults caused or materially contributed to plaintiff’s injuries.  Liability was not a live issue at trial.  Nor was it an issue on appeal.  However, this was not an appropriate case in which to use the material contribution test to establish causation.

[29]         The appellant’s argument that other factors contributed to the respondent’s injuries did not make it “impossible” to prove causation in this case using the “but for” test. As Erik S. Knutsen,^[1] points out in his paper “Clarifying Causation in Tort” (2010) 33 Dal. L.J. 153, at p. 169: “Successive and cumulative injury cases, including those involving pre-existing conditions, can also satisfactorily meet the “but for” test”.  This is because a “defendant’s negligence need only be “a” cause, not “the” cause [of the injury].”  It was therefore an error for the trial judge to instruct the jury in accordance with the material contribution test.

…

ii)    Principles of damages

[31]         Once causation, and therefore liability, has been established, a separate inquiry must be conducted to assess the extent of the harm.  Different principles govern the two analyses.  Causation is concerned with connecting the defendant’s fault to the plaintiff’s harm.  Damages are concerned with repairing that harm by putting the plaintiff in the same position he or she would have been in but for the defendant’s fault.

[32]         While a finding of causation equates to responsibility for the entire injury, a defendant is not required to put the plaintiff in a better position than his or her original one.  Major J. explained this principle in Athey, at para. 32:

The essential purpose and most basic principle of tort law is that the plaintiff must be placed in the position he or she would have been in absent the defendant’s negligence (the “original position”).  However, the plaintiff is not to be placed in a position better than his or her original one.  It is therefore necessary not only to determine the plaintiff’s position after the tort but also to assess what “original position” would have been.  It is the difference between these positions, the “original position” and the “injured position”, which is the plaintiff’s loss.

[33]         Certain principles may limit the extent of a plaintiff’s damages notwithstanding a finding that the defendant caused the injuries.  Two such principles formed the thrust of the appellant’s case at trial – the crumbling skull principle and the principle of successive tortious events.  The appellant’s position was that:

1.      Even absent the sexual assaults, there was a measurable risk that because of the other incidents, the respondent would have suffered from depression or post-traumatic stress and, therefore, part of the damages she suffered would have occurred in any event (the crumbling skull principle); and

2.      The tortfeasors responsible for the other tortious incidents caused or contributed to the depression and post-traumatic stress now suffered by the respondent (the successive tortious events).