Expert Opinion Evidence – Impartiality, Independence and Bias

12.              The Rules of Civil Procedure outline the duty of an expert as follows: (a) to provide opinion evidence that is fair, objective and non-partisan; (b) to provide opinion evidence that is related only to matters that are within the expert’s area of expertise; and (c) to provide such additional assistance as the court may require.[6]

13.              An expert witness’ duty prevails over any obligation owed by the expert to a party. A proposed expert witness who is unable or unwilling to comply with this duty is not qualified to give expert opinion evidence and should not be permitted to do so.[7]

14.              In White Burgess, the Supreme Court of Canada cited the English case “Ikarian Reefer” for the impartiality and independence of expert opinion evidence:

1.  Expert evidence presented to the court should be, and should be seen to be, the independent product of the expert uninfluenced as to form or content by the exigencies of litigation . . . .

2.  An expert witness should provide independent assistance to the court by way of objective unbiased opinion in relation to matters within his [or her] expertise… An expert witness in the High Court should never assume the role of an advocate.[8]

15.              In White Burgess, the Supreme Court of Canada stated that the three related concepts underlie an expert’s duties: impartiality, independence, and absence of bias:

The expert’s opinion must be impartial in the sense that it reflects an objective assessment of the questions at hand. It must be independent in the sense that it is the product of the expert’s independent judgment, uninfluenced by who has retained him or her or the outcome of the litigation.  It must be unbiased in the sense that it does not unfairly favour one party’s position over another. The acid test is whether the expert’s opinion would not change regardless of which party retained him or her.[9]

16.              When considering the independence of an expert, the question is not whether a reasonable person would consider that the expert is not independent. Rather, what must be determined is whether the expert’s lack of independence renders him incapable of giving an impartial opinion in the specific circumstances of the case.[10]

19.              In Nguyen v. Szot, the opinion evidence of Dr. Mamelak (one of the plaintiff’s experts in this case) was not accepted in circumstances where the court determined that Dr. Mamelak had crossed the line by vociferously advocating on behalf of the plaintiff. The court found that his “subjective advocacy greatly diminished his credibility” and did not accept Dr. Mamalek’s evidence on the plaintiff’s impairment.  The plaintiff did not meet the threshold.^[13]Dr. Mamalek’s role as an advocate is dealt with below regarding this plaintiff. 

48.              I agree that Dr. Mamelak’s advocacy in the trial bears striking similarity to his conduct which was criticized and rejected by the court in Nguyen v. Szot, 2017 ONSC 3705 (CanLII). Frankly, I have never been exposed to such an advocate who was defensive, combative and launched into speeches. I put no weight on his evidence (see pages 24, 25, 45, 46, 51-53, 74-77, 80 from his transcript of his trial evidence).

55.              The opinion of Dr. Rosebush, the defence psychiatric expert, prevails, over the opinion of Dr. Mamelak.  I suspect that had a voir dire taken place regarding Dr. Mamelak’s ability to testify as an expert that it would have resulted in an exclusion of his evidence.