One of the recognized objections to the introduction of expert opinion evidence in a personal injury trial relates to the opinion relying on novel or untested scientific theory.  Reasons for judgement were released last week by the BC Court of Appeal addressing this objection and taking a practical view of the benefits of experts providing opinions based on their years of experience in a clinical setting.
In last week’s case (Cassells v. Ladolcetta) the Plaintiff was injured in a 2005 collision.  He suffered from a pre-existing condition, namely psoriatic arthritis.  The Plaintiff presented evidence that this condition was aggravated due to the trauma of the collision.  This evidence was accepted at trial and damages were assessed accordingly.
The Defendant appealed arguing the medical opinion was based on novel science.  The BC Court of Appeal disagreed finding the foundation for an expert opinion can be laid based on clinical experience.  In dismissing the Appeal the Court provide the following reasons:

[13] The defendants challenged reliance on Dr. Gladman’s evidence on essentially the same basis at trial as they do now.  Their contention was and remains that her opinion was based on what they say is novel science: no scientific data established, beyond mere speculation, that her “theory” was valid.  They say that at most the theory is an unproven hypothesis.  They cite the criteria for evaluating the soundness of novel science found in R. v. Mohan, [1994] 2 S.C.R. 9, 89 C.C.C. (3d) 402, as drawn from Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579, 113 S.Ct. 2786 (1993), and discussed in Taylor v. Liong, 2007 BCSC 231, [2007] 7 W.W.R. 50.

[14] The judge said the criteria pertain to the admissibility of expert evidence.  Admissibility requires the weighing of threshold reliability.  No issue had been taken with the admissibility of Dr. Gladman’s opinion which it was evident is consistent with a widely held belief in the scientific community.  Quoting from R. v. Terceira (1998), 38 O.R. (3d) 175, 123 C.C.C. (3d) 1 (C.A.), aff’d [1999] 3 S.C.R. 866, to the effect the threshold test of reliability must adapt to changing circumstances, the judge said that, in the face of studies that did reflect a wide provisional acceptance of Dr. Gladman’s hypothesis, the lack of a conclusive study should not be fatal to either the admissibility or the weight of her opinion.

[15] Unlike instances where, as in Taylor, the opinion of an expert which is shown to be no more than uncertain theory has been ruled inadmissible, here, as the judge said, Dr. Gladman expressed her opinion on the basis of what she said she had seen in response to trauma among her patients with psoriatic arthritis.  What is said to be the inconclusive literature she referenced was, as the judge said, not the only foundation for the opinion she held.  It was an opinion based on thirty years of her experience.

[16] The judge reached the ultimate conclusion he did concerning the aggravation of the respondent’s psoriasis and psoriatic arthritis relying on the evidence of the various physicians whose opinions he had to consider.  Dr. Gladman’s opinion on the effect of trauma on psoriatic arthritis is consistent with the other opinion evidence which the judge found acceptable, as well as with the evidence of the respondent’s medical condition and, for that matter, the deterioration in his life after the accident.  I do not consider there to be any sound basis on which it can now be said the judge made an overriding and palpable error in concluding the respondent’s psoriasis and psoriatic arthritis were aggravated by trauma and stress attributable to the accident by relying on Dr. Gladman’s opinion.