The Court of Appeal recently overturned a dismissal of a medical malpractice action due to improper expert evidence.
In Parliament v. Conley, 2021 ONCA 261, a baby was diagnosed with hydrocephalus (an accumulation of fluid within the brain) when he was around four month old. He is now 21 years old and has cognitive and physical disabilities. He and his parents sued two doctors alleging that they delayed in diagnosing and treating the problem, causing brain damage.
One of the defendants’ experts was Dr. Bruce, an expert in family medicine and episodic care. The Court of Appeal held that there were several problems with Dr. Bruce’s evidence. He exceeded his role as an expert when he opined on the credibility and reliability of the treating doctors and the mother. For example, he observed that the mother was untruthful and could not accurately remember.
The Court of Appeal stated that the expression of an opinion as to the credibility of witnesses is a breach of an expert’s duty to be independent. The ultimate conclusion as to the credibility or truthfulness of a particular witness is for the trier of fact and is not the proper subject of expert opinion.
The Court of Appeal noted that a trial judge has a continuing gatekeeping role. The trial judge could have, in the absence of the jury, invited submissions as to the content of a mid-trial instruction that the jury ignore any and all of Dr. Bruce’s expressions as to the credibility or reliability of the witnesses. The trial judge could have also included a very clear and specific instruction on this point in the final charge.
At trial, the plaintiffs did not object to Dr. Bruce’s impugned evidence. The general principle is that a party in a civil case should not bring an appeal on the basis of some aspect of the lower court proceeding to which it did not object. The failure to object at trial is not treated lightly and is usually fatal to an appeal on that point.
However, a new trial may be ordered in cases where the appellate court is satisfied that it is necessary in the interests of justice. The focus should be on whether there was a substantial wrong or miscarriage of justice.
The Court of Appeal held that there is a very real possibility that Dr. Bruce’s evidence on credibility and reliability played a significant role in the jury’s decision. The evidence was highly prejudicial to the plaintiffs and tainted the jury’s verdict.
As a result, the Court of Appeal concluded that there has been a miscarriage of justice and that a new trial is required.