How and When to Safeguard the Independence of the Expert

  • November 25, 2021
  • Katherine L. Shadbolt

This paper highlights cases where an Ontario Court held that expert evidence was not admissible for not meeting the test set out in White Burgess Langille Inman v. Abbott and Haliburton Co., 2015 SCC 23 (“White Burgess”). It will:

  1. review the test for admissibility as set out in White Burgess;
  2. discuss four subsequent and notable Ontario cases where expert evidence was not admitted; and
  3. provide practical tips on how Counsel can safeguard the independence of the expert.

(i) The Legal Test for Admissibility of an Expert Witness

In White Burgess, at paras 23-24, the Supreme Court of Canada provided clarity and guidance regarding admissibility of expert evidence. Cromwell J., writing for the Court, adopted the two-step approach in R. v. Abbey, 2009 ONCA 624, with minor adjustments:

  1. “At the first step the proponent of the evidence must establish the threshold requirements of admissibility.” These are the four traditional “threshold requirements” established in R. v. Mohan, [1994] 2 SCR 9: 1) relevance; 2) necessity in assisting the trier of fact; 3) the absence of an exclusionary rule; and 4) a properly qualified expert. And, “in addition, in the case of an opinion based on novel or contested science or science used for a novel purpose, the reliability of the underlying science for that purpose…”
  2. The second component is a “discretionary gatekeeping step” where the “judge balances the potential risks and benefits of admitting the evidence in order to decide whether the potential benefits justify the risks.” It is a cost-benefit analysis where the Court must determine whether the expert evidence should be admitted because its probative value outweighs its prejudicial effect.

As Cromwell J. observed, at para 33, “there is a broad consensus about the nature of an expert’s duty being to the Court. There is no such consensus, however, about how that duty relates to the admissibility of an expert’s evidence.” This raised two important questions in White Burgess namely “should the elements of this duty go to admissibility of this evidence rather than simply to its weight? And, if so, is there a threshold admissibility requirement in relation to the independence and impartiality?”

Cromwell J. confirmed, at para 40, that the potential bias of an expert must be considered in the admissibility of the expert’s testimony at the initial threshold inquiry and once that threshold is met, it must also be considered as the Court exercises its gatekeeping role and its discretion to exclude evidence.

In other words, as Cromwell J. described, at para 2: “Expert witnesses have a special duty to the Court to provide fair, objective and non-partisan assistance. A proposed 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.”