The Supreme Court of Canada recently outlined in White Burgess Langille Inman v. Abbott and Haliburton Co., 2015 SCC 23 (“White Burgess”) that lack of independence of an expert report can go to the threshold question of admissibility. This case builds upon the principles in the landmark decision R v. Mohan,  2 S.C.R. 9 (“Mohan”), which serves as the starting point for assessing the admissibility of expert evidence. Mohan sets out four threshold requirements for the admissibility of an expert report, which are:
Absence of an exclusionary rule; and
A properly qualified expert.
However, passing the four Mohan criteria threshold is only the first step. Rule 11-2 of our Rules of Court states that in giving an opinion to the court, an expert has a duty to assist the court and is not to be advocate for any party. Thus, after the Mohan criteria are satisfied, the trial judge serves a gatekeeper function and assesses whether the expert evidence is beneficial to the trial process.
In White Burgess, the Court explained that expert witnesses have a duty to the court to give fair, objective, non-partisan opinion evidence. There are three concepts which underpin this requirement. First, expert opinion evidence must be impartial, reflecting an objective assessment. Second, the evidence must be independent, in the sense that it is truly the product of the expert’s own judgement, and not influenced by the party who has retained them. Finally, the evidence must be unbiased in that it does not unfairly favour a particular party. The acid test is whether the expert’s opinion would not change regardless of the party that retained them.
The Court’s analysis in White Burgess is especially important for lawyers when instructing their respective experts, as most inadmissible reports will actually satisfy the Mohan criteria, but fail by virtue of obvious bias. The Court held that exclusion at the threshold stage occurs only in very clear cases. Some examples include situations where:
the expert has a direct financial interest in the outcome of litigation;
the expert has a close familial relationship to a party;
the proposed expert is likely to incur professional liability if the opinion evidence is not accepted by the court; and
the expert in their proposed evidence assumes the role of an advocate for a party.
Of course, an employment relationship with a party is insufficient to render expert evidence inadmissible at the threshold stage. The reality of litigation is that experts are generally retained by law firms and are financially compensated for their work product. However, lawyers should take note of the Court’s commentary in White Burgess, as it sheds light on common pitfalls which can be avoided by a well thought out instruction letter. Experts have a special place in litigation as they are permitted to provide opinion evidence in their area(s) of expertise, where others are not permitted. However, the reality is that most experts do not have any legal training. Lawyers should take the time to consider exactly what evidence they are hoping to attain from an expert, and ensure that the expert’s opinion(s) is/are appropriately restricted. Some common pitfalls which judges are loathe to see in an expert report include:
providing opinion evidence outside of their area of expertise;
the expert usurping the role of the judge by making finds of fact, or worse, drawing legal conclusions in addition to providing opinion evidence;
providing irrelevant and superfluous information in their report which is of little probative value, which can make it difficult for the trier of fact to differentiate between assumed facts and opinion;
ignoring material inaccuracies in forensic evidence which does not favour the party who retained them, including relying on other expert reports which clearly make the same mistake;
including inappropriate and inflammatory language;
failing to properly set out the factual basis of the opinion, and/or failing to outline what documents were relied upon in providing the opinion;
Rule 11-2 and the reasons in White Burgess clearly articulate that there is a clear duty upon an expert to assist the court and not be an advocate for a party. There are straightforward measures that lawyers can take to assist an expert in avoiding seemingly obvious, but all too common pitfalls. Avoiding these errors is crucial, as having an expert report deemed inadmissible can have damaging effects to a litigant. Lawyers are the ones with legal training, and the onus is on them to assist their experts. An expert report must be independent and unbiased, but proper instructions which precisely target the opinion sought is critical. Lawyers can also do their own background research on a particular expert to see how their evidence has been treated by the courts in the past. A little bit of effort can go a long way to avoid repeating a mistake or committing a new one.
Click here to see The Supreme Court of Canada's Judgements on the case of White Burgess Langille Inman v. Abbott and Haliburton Co.