Thought leadership from our experts

Product liability and the evolving landscape of expert evidence admissibility in Canada

Expert evidence is crucial in almost all Canadian product liability cases. Canadian courts now regularly receive objective opinions on defect allegations; on whether the defect caused the damages allegedly suffered by the plaintiff(s); and on how those damages should be quantified.

For many decades, there was no organized principled approach to the admissibility of expert evidence in products cases and there was no appellate authority on how to properly test the reliability of that evidence or the qualifications and independence of the expert.

In the class action context, courts were hesitant to decline certification of product liability cases so long as some expert evidence was tendered on behalf of the proposed representative plaintiff, despite concerns about the qualifications, independence, and impartiality of the expert or the reliability of the evidence being tendered. In other product liability cases, plaintiffs with cases of doubtful merit could avoid summary dismissal of their cases by tendering almost any expert report and (often successfully) arguing that a trial was required in order to weigh the expert evidence.

The evolution toward some rigour in considering expert testimony began with the Supreme Court of Canada's 1994 decision in R v Mohan,1 where the Court set out basic principles for the admissibility of properly qualified expert evidence. However, the Supreme Court in Mohan did not articulate a test or provide any guidance beyond a passing reference to the requirement that the expert must have "acquired special or peculiar knowledge through study or experience in respect of the matters on which he or she undertakes to testify" in order to have his or her testimony admitted in to evidence.2

In 2007, the Honourable Justice Coulter Osborne, a retired judge of the Court of Appeal for Ontario, investigating potential reforms to Ontario's Rules of Civil Procedure, remarked that unqualified "hired guns" and expert "opinions for sale" continued to be one of the most common complaints about purported expert testimony voiced by litigators in Ontario.3

Justice Osborne's recommendations caused the introduction of a rule in Ontario's Rules of Civil Procedure requiring experts to acknowledge in writing that their duty is to the court, not to the client by which he or she was retained, and that they have an obligation to give objective, impartial evidence.4 Yet, expert testimony continued to be admitted with no real analysis regarding qualifications and independence, so long as the expert signed a form acknowledging his or her duties to the court.

The past year, however, marked what may prove to be a watershed in the law relevant to expert opinions in Canada. Two Supreme Court of Canada decisions handed down in 2015 acknowledged the problem of unqualified and biased experts, and provided some guidelines for dealing with what has become a recurring issue in Canadian legal proceedings.

The Supreme Court began laying the groundwork for a test to disqualify impartial and biased experts in Movement laigue quebecois v Saguenay (City).5 The Court in Saguenay espoused the principle that an "expert's opinion must be independent, impartial and objective, and given with a view to providing assistance to the decision maker".6 The Court stated, without providing much substantive guidance, that lower courts should consider an expert's independence and objectivity when the expert is being qualified, at the admissibility stage, but that a trial judge's findings on the issue will be entitled to deference on appeal.

The Court in Saguenay articulated a high standard for disqualification of expert testimony, requiring the expert to be actually biased or lacking independence, rather than the appearance of bias or partiality.7 The question for the trial judge to ask is "whether the expert's lack of independence renders him or her incapable of giving an impartial opinion in the specific circumstances of the case".8

The skeletal framework articulated in Saguenay was fleshed two weeks later in the Supreme Court's decision in White Burgess Langille Inman v. Abbott and Haliburton Co.9, where the court clarified that the duty to give impartial, independent, and unbiased evidence permeates the analysis of expert evidence both before and after it is admitted. The Court in White Burgess addressed head-on the role of an expert's impartiality and independence, confirming unequivocally that a lack of independence or impartiality must be considered prior to admitting the expert's opinion.10

The Court described issues of bias and independence of experts as a "matter of fact and degree".11 The Court described the test at the admissibility stage as "not particularly onerous", and expert evidence will only be excluded in "clear cases" where the expert is unwilling or unable to comply with their duties to the court, but it is a threshold that must nevertheless be satisfied.12 The Court gave some examples of circumstances where bias or lack of independence might lead to inadmissibility at the threshold stage:

1. the proposed expert has a direct financial interest in the outcome of the litigation;

2. the proposed expert has a close familial relationship with one of the parties;

3. the proposed expert may incur professional liability if his or her opinion is not accepted by the court; or

4. the proposed expert assumes the role of an advocate for a party.13

Even if it not a "clear" or extreme case of bias or partiality, the court must nevertheless consider, before admitting the expert's testimony, whether the bias or partiality possessed by the proposed expert will have a prejudicial effect that will outweigh the probative value of the evidence.14 In other words, the court must perform a cost-benefit analysis of admitting the evidence.

Further, even if the expert's testimony is admitted, the expert's objectivity and impartiality should still be assessed again when his or her evidence is weighed.15

The test articulated by the Supreme Court is less stringent than the Daubert standard16 governing the admissibility of expert evidence in the United States. The decisions in Saguenay and White Burgess nevertheless mark a long overdue shift in Canadian law towards applying at least a minimal amount of analytical rigour to the issues of objectivity and independence seriously at the admissibility stage.

The Supreme Court's decisions in White Burgess and Saguenay will likely feature in product liability claims, where experts often take on multiple roles in relation to one legal proceeding. For instance, in a fire "origin and cause" case where it is alleged that a defectively designed or manufactured product caused the fire, one expert may have been involved in the immediate aftermath of the fire, retained by an insurer to supervise the clean-up and lead the origin and cause investigation. That same expert may later be asked to provide an opinion supporting a subrogated claim brought by the same insurer, and then defend, in the course of the litigation, against allegations of spoliation or inadequate investigation. The expert in this situation could have difficulty maintaining objectivity insofar as the adequacy of an investigation he or she led is being challenged.

The Supreme Court's decisions in White Burgess and Saguenay mean that trial judges will now be required to at least consider whether an expert has a financial interest or assumed the role of an advocate, such that the expert is unable to comply with his or her duty of objectivity and independence.


  1. (1994) 2 SCR 1 (Mohan).
  2. Ibid., at 25.
  3. Hon. Coulter A. Osborne, QC, Civil Justice Reform Project: Summary of Findings & Recommendations, 2007. <https://www.attorneygeneral.jus.gov.on.ca/english/about/pubs/cjrp/CJRP-Report_EN.pdf>.
  4. Rules of Civil Procedure, RPO 1994, Reg 194, r. 4.01.
  5. 2015 SCC 16 (Sanguenay)
  6. Ibid., at para 105.
  7. Ibid.
  8. Ibid.
  9. 2015 SCC 23 (White Burgess)
  10. Ibid., at paras 33-34, 45.
  11. Ibid., at para 50.
  12. Ibid., at para 49.
  13. Ibid.
  14. Ibid., at para 54.
  15. Ibid., at para 32.
  16. Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579 (1993)