How Far Can an Expert Go Without Losing Credibility in Court?

The Role of the Expert in Court: An Opportunity for Impartiality

The expert is not the spokesperson for the party who appointed them. Their primary mission is to provide the court with objective, impartial and thorough information. This mission supersedes the interests of the party that commissioned the expert and requires them to demonstrate professionalism, independence and complete impartiality.

Their role is to enlighten the court with impartial expert testimony in a field within their area of expertise. Their obligations are set out in the Code of Civil Procedure. An expert who seriously fails to fulfill their duties or deviates from the role entrusted to them may have their expert report rejected or, in the most serious cases, may be denied qualification as an expert.

Admissibility and Probative Value of an Expert Opinion: What’s the Difference?

It’s important to distinguish between these two concepts, since an expert opinion can be challenged on two levels: first, with regard to its admissibility, when the conditions for admitting it as evidence are not met (in particular, when the expert seriously fails to meet their obligations of independence and impartiality); second, with regard to its probative value, when the expert’s conclusions are based on a flawed methodology, unfounded assumptions or an incomplete analysis of the evidence.

As a general rule, the admissibility of an expert opinion should be recognized by the courts. The refusal to qualify an expert is an exceptional measure that should be reserved only for clear-cut cases in which the expert is unable or unwilling to provide a fair, objective and impartial opinion. In certain cases, such as Angeli v. Lévesque, the court nevertheless concluded that this threshold had been met and refused to qualify the witness as an expert or to admit his report.

When Can a Court Refuse to Recognize an Expert? 

The purpose of expert testimony is to help the court better understand technical, scientific or specialized issues that go beyond ordinary knowledge. However, the court may refuse to recognize a witness as an expert if it determines that the witness does not meet the fundamental requirement of impartiality that applies to all experts. This may be the case, in particular, when the latter:

• Adopts their client’s position to the point of becoming the client’s advocate;
• Ignores or disregards statements made by their own client;
• Denies any admissions made by their client during the hearing;
• Disregards evidence that is inconsistent with their own opinion;
• Ignores important information;
• Makes decisions on matters outside their area of expertise;
• Takes the place of the judge in evaluating the evidence and deciding questions of law;
• Expresses conclusions that are more akin to a legal argument than to an expert analysis.

Under such circumstances, the court may conclude that the expert is unable or unwilling to fulfill their fundamental obligations of independence and impartiality toward the court. The court may then refuse to qualify them as an expert and exclude their testimony.

In the case of Angeli v. Lévesque, the judge reached this conclusion in part because the witness had expressed an opinion in a field in which he lacked the necessary expertise, suspected the existence of conspiracies simply because he was not convinced of a document’s authenticity, had ignored or contradicted certain statements and admissions made by his own client, had disregarded evidence that did not align with his opinion, and had, on several occasions, encroached upon the court’s role in evaluating the evidence and deciding questions of law.

The Probative Value of an Expert Report: Under What Circumstances Can It Be Disregarded?

If the expert report is admitted into evidence and the witness is qualified as an expert, the court must then analyze its content and evidentiary value. The expert report must be sufficiently detailed and well-reasoned to enable the court to understand the facts analyzed, the expert’s line of reasoning, and the conclusions reached. In particular, it must describe the methodology used and demonstrate how the proposed conclusions are supported by the evidence.

Even when an expert is recognized as such, the evidentiary value of their opinion and report remains to be determined. The court retains the discretion to assess the usefulness and evidentiary value of the expert opinion and, in certain exceptional cases, to set it aside when its usefulness is so limited that it is clearly outweighed by its prejudicial effect. Rejection of the report may be justified when it:

• Is based on factual premises that are erroneous or inconsistent with the evidence presented;
• Downplays or contradicts accepted facts;
• Ignores important evidence or refuses to address it properly;
• Is based on theoretical, speculative or unsubstantiated assumptions;
• Contains opinions that go beyond the expert’s mandate or that fall outside the expert’s area of expertise;
• Reveals an approach that is more akin to that of an investigator than to that of an independent expert.

Consequently, the deficiencies in the report’s content may be such that the court concludes that the report is unlikely to provide it with adequate guidance in making its decision. The court may then assign little or no evidential value to it, or even disregard it entirely.

How Can the Credibility of an Expert and Their Report Be Maintained?

The Angeli v. Lévesque decision reiterates that an expert must not be an advocate for their client’s cause, but rather an assistant to the court, whose role is to provide objective and impartial guidance. The parties who retain the services of an expert must therefore ensure that the expert is able to provide an opinion based on all the evidence, that the expert fully understands their duty of independence, objectivity and impartiality, as well as the responsibility to inform the court, and that the expert can fulfill these obligations throughout the course of their mandate.

Otherwise, the retaining parties run the risk of having the qualification as expert challenged by the opposing party, or even rejected by the court, or of having the expert’s report dismissed. Such a decision has serious consequences for the party that retained the expert, as it is then left without an expert report to submit to the court, which constitutes a significant gap in the party’s case. The court may, however, allow another expert report to be prepared.

Seeking Assistance in a Shareholder Dispute

Issues related to expert testimony frequently arise in commercial disputes, particularly in those between shareholders as well as oppression claims, where expert testimony often concerns the value of shares, investigative forensic accounting analysis, or corporate management.

If you have any questions regarding the preparation, challenge or use of an expert report in such a case, please contact our shareholder dispute or civil and commercial litigation teams. They will be able to assess the available options and develop a strategy tailored to your situation.

You may also contact Stéphan Charles-Grenon, Partner, Lawyer and Head of the Litigation Group in the city of Québec, whose practice focuses on commercial litigation and shareholder disputes, or Isabel Pouliot, Partner and Commercial Litigation and Shareholder Dispute Lawyer in the city of Québec. Coralie Martineau, Véronique Milot and Rosa-Li Hébert, civil and commercial litigation lawyers, can also assist you.