Allegations of expert opinion bias can upend a legal party's case. This is particularly true in medical malpractice cases, in which cases often come down to a 'battle of experts'. We provide a review of recent decisions involving allegations of expert opinion bias, and tips for how to avoid this issue with your own litigation experts.
Written by Joseph Ur, JSU LAW
Pictured above: an expert, with a few things on their mind.
Experts are the driving force behind factually complex litigation, including in medical malpractice and professional negligence cases. Often these cases are brought on the back of she-said/he-said sets of facts, incomplete notes, and fallible memories. Within that framework, experts present a unique challenge in litigation – despite their involvement in an adversarial process, experts must try to stay impartial.
In most cases, experts are entirely uninvolved in the underlying facts of a lawsuit; they are commentators, used to provide context outside of the knowledge and experience of a judge or jury. However, experts in litigation are retained by sides in opposition, and experts are often forced to base their opinions on a set of facts that has been coloured by the lens of the party that hired them.
While expert evidence is used as the foundation upon which a party advances and argues their case, the experts themselves cannot step into the role of an advocate. This can be difficult to avoid. Any attempts by an expert to assess credibility, pick one side’s facts over the other, or comment outside of the scope of their expertise could be characterized as bias.
In the last decade, it seems to have become more commonplace, and more well-received by courts, for litigators to allege that opposing experts are not impartial or biased in their opinions. An allegation of expert bias is low-risk/high reward – if argued successfully, legal counsel can devalue the opposing expert’s opinion or have the expert excluded from providing the opinion altogether. In any instance, allegations of expert bias can derail a legal party’s entire case, and can be fatal in medical malpractice cases in particular, which are seldom successful without the backing of expert evidence.
It has become vitally important for any litigator that makes use of expert witnesses and expert reports to be proactive in avoiding pitfalls of bias, particularly if a case goes to trial. Lawyers should make note of the recent line of case-law in this area when they retain, instruct, and work with experts. Lawyers working with experts should emphasize to them their intended role as a fair and impartial assistant to the court, as well as the following key tips:
1) Experts should be explicit about their assumptions.
2) Experts should be willing to make concessions.
3) Experts are not advocates.
Recent notable cases and principles
The seminal case on the duty of expert witnesses and expert impartiality is the Supreme Court of Canada’s decision in White Burgess Langille Inman v Abbott and Haliburton Co., which set out the following key points on the admissibility of expert opinion evidence:
1) An expert must be fair, objective and non-partisan. Their duty to assist the court overrides their obligation to the party calling them. If a witness is unable or unwilling to fulfill that duty, they do not qualify to perform the role of an expert and their evidence should be excluded;
2) Absent a challenge to the witness’s impartiality, the expert’s acceptance of their duty will generally be sufficient to establish their impartiality;
3) The burden is then on the party opposing the admission of the evidence to show that there is a realistic concern that the expert is unable and/or unwilling to comply with their duty. The burden to establish admissibility remains on the party proposing to call the evidence; and
4) It is rare that a proposed expert’s evidence would be ruled inadmissible on this basis. Exclusion should only occur in very clear cases in which the proposed expert is unable or unwilling to provide the court with fair, objective and non-partisan evidence. Anything less should not lead to exclusion, but should be taken into account in the overall weight of the evidence.[1]
Despite the ‘rarity’ of expert evidence being ruled inadmissible, and the Supreme Court’s allowance for a grey area (i.e.: ‘anything less’ than the expert’s inability or unwillingness to be impartial) litigants will always be keen to allege bias in an opposing expert’s opinion and will often have success in doing so. The mere suggestion of bias can sow doubt in the trier of fact’s mind, or can result in the successful exclusion of an expert’s evidence altogether.
In the 2019 medical malpractice case Parliament et al v Conley, the plaintiffs successfully brought a mid-trial motion to have the defendant physicians’ standard of care expert excluded at trial.[2] They did so based on the proposed expert’s alleged bias both in her expert reports and in a voir dire on qualification.
The expert’s alleged bias was in her failure to refer to or consider the plaintiffs’ discovery evidence in her expert reports. The expert instead relied entirely on the defendants’ version of events when coming to her opinions. While the defendants argued that any allegations of bias could be dealt with in cross-examination, the trial judge excluded the expert’s evidence outright, having found that the expert “whole-heartedly accepted the testimony of both doctors as the gospel truth while high-handedly rejecting the plaintiffs’ evidence”.[3]
In excluding the expert’s evidence, the trial judge in Parliament relied on the Ontario Court of Appeal decision in Bruff-Murphy v Gunawardena, in which a trial decision was overturned for the judge’s failure to exclude biased expert testimony. In Bruff-Murphy, the expert psychiatrist was allegedly biased for his attempts to find and draw attention to inconsistencies in the plaintiff’s story. The expert “torqued… results [of testing] so that they produced results that supported his conclusion”, and attacked the plaintiff’s credibility outright. In ordering a new trial, the Court of Appeal found that there was a real concern in the expert usurping the role of the trier of fact, and that the expert acted as an advocate for the defendants.[4]
The Parliament case also produced another noteworthy decision on expert bias when the jury verdict in favour of the defendants went to the Ontario Court of Appeal. The Court, in similar reliance on its own decision in Bruff-Murphy, overturned the jury verdict and ordered a new trial due to the bias of the defendants’ other standard of care expert.[5]
Interestingly, the second expert was deemed to be biased for essentially the same reasons as was the defendants’ first expert, whose evidence was excluded in the mid-trial motion. The Court of Appeal held that the expert “opined on the credibility of the parties in his oral testimony”, and that he was partial in his belief and reliance on the defendants’ evidence, and not the plaintiffs’. Because credibility and reliability of the parties were central issues for the jury to decide, the Court found that the expert was biased, and his evidence should have been excluded.[6]
The failures by the experts in Parliament came down to their perceived assessments of credibility. However, there is a fine line between advocating for one side and relying on one side’s version of events in coming to an opinion. As a sidenote, having been involved as counsel in the Parliament case, I recognize that I come to this with my own inherent biases. That said, it would be interesting to know whether either of the experts’ opinions in Parliament would have been deemed acceptable had they explicitly said in their reports and in their oral evidence that their opinions were based on the assumption that the defendants’ recollection of events was correct. It is trite law – from the Supreme Court of Canada’s 1982 decision in R v Abbey – that the weight accorded to an expert’s opinion is dependant on the facts underlying the opinion being borne out in the evidence. If the assumed facts prove to be incorrect, the expert’s opinion becomes worthless.[7]
In the recent medical malpractice case Fortune-Ozoike v Wal-Mart Canada Corp., while the trial judge did not exclude the defendants’ experts’ evidence, she entirely discounted both of their experts’ opinions in her reasons for judgment, and admonished the experts’ performances at trial for their alleged biases.[8]
The trial judge disregarded the first expert’s opinion for their failure on cross examination to make concessions that there was a breach of the standard of care, despite it being the ‘logical conclusion’ of the expert’s evidence. The trial judge wrote:
During his cross-examination, [the expert] was extremely reluctant to admit obvious statements in relation to Dr. Lian’s failure to make notes of his assessment at 1 a.m. It is only after reviewing the policy statement issued by the College of Physicians and Surgeons of Ontario on medical records… that he conceded … that Dr. Lian had a legal obligation to make notes. However, he refused to acknowledge that the standard of care of a practicing physician required them to make notes of their assessments of patients, and he said that he could not comment on the standard of care with respect to handwritten notes, or any notes. [The expert] stated that he did not know whether the standard of care required emergency room physicians to make notes of their assessments of patients. He later said that he did not think that failing to make a note was a breach of the standard of care, but he subsequently reverted to his position that he was not an expert with respect to providing the standard of care for handwritten notes.[9]
The trial judge agreed with the plaintiff’s argument that the expert’s “refusal to make obvious concessions [was] a hallmark of expert who has taken on the role of advocate.”[10] The trial judge went on to ignore the evidence of the defendant’s second standard of care expert, referring to their performance as an expert as “deplorable”, and that of an advocate:
In cross-examination, [the expert] gave non-responsive answers to simple questions on multiple occasions, he attempted to resile from statements contained in his report, and he refused to admit obvious statements. In addition, he gave answers that made no sense in light of his own reports, the evidence given by Dr. Lai during his examination for discovery and the literature that was accepted as authoritative in the area of orthopaedic medicine, including by [the expert] himself. He also repeatedly referred to “management strategies”, a concept that is not mentioned in his reports and the contents and relevance of which were not explained in any detail in relation to this particular case.[11]
Other recent notable cases – primarily in medical malpractice – in which experts have been accused of bias include:
In Finnigan et al v Lee, the trial judge found that the plaintiff’s expert took on the role of an advocate and was less credible than the defendant’s expert, whose evidence she preferred. The expert “seemed ready to find all of the defendant’s actions to be breaches of the standard of care. His opinions were not consistent throughout. In examination in chief, he appeared unwavering regarding his opinions but, in cross-examination, conceded that numerous of the actions he found to be in breach of standards of care were not actually so… His reports were not always consistent with his evidence at trial, which seemed intent on establishing the defendant’s liability.”[12]
In Hasan v Trillium Health Centre Mississauga, the trial judge preferred the plaintiff’s expert’s evidence, having been left with “very serious concerns over [the defendant’s expert’s] reliability as an impartial expert and his understanding of his obligations to the court.” The defendant’s expert was found to have deliberately minimized the defendant’s clear missteps as an emergency physician as insignificant, and further speculated on the defendant’s thought processes without evidence to support his conclusions.[13]
In Leckie v Chaiton, the trial judge preferred the defendant’s expert’s evidence to that of the plaintiff’s expert, who the trial judge deemed to take on the role of an advocate. The trial judge discounted the expert’s evidence due to: (i) his approach being overly theoretical and “divorced from what was actually happening in the community setting” at the material time; (ii) his failure to consider the defendant’s evidence of his usual practice; and (iii) his attempts to hold the defendant to a standard of care considerably higher than that which he acknowledged applies to himself and other physicians.[14]
In Hamelin v Mikkelsen et al, the trial judge excluded the plaintiff’s expert from giving evidence in a jury trial. The expert was found to have relied on internet research – performed only after forming his opinion – that conformed to his conclusions, while specifically ignoring any unsupportive research findings. The expert also refused to acknowledge the expertise of the defendant’s expert in a “partisan” rebuttal report.[15]
Takeaways, and instructions to experts
Allegations of bias are low-risk/high-reward for the accusing party. In medical malpractice cases, which can rarely be brought without the backing of expert evidence, the exclusion of an expert’s evidence can be fatal. The stakes for litigators who are concerned with their own expert’s perceived biases are therefore extremely high, particularly in advance of trial.
Counsel should be proactive with their instruction of experts to avoid any pitfalls in expert reports or in an expert’s testimony, and take the following into account:
1) Experts should be explicit about their assumptions.
This is a practice point that I have taken forward with me for all my medical malpractice cases. In coming to their opinions, experts need to consider all the material for a case, including the opposing party’s discovery evidence. If the discovery evidence is diametrically opposed on some key facts, the expert should be explicit as to which facts or which evidence they are relying upon in coming to their conclusions, and they should note this as an assumption underpinning their opinion.
In medical malpractice cases, a medical practitioner will often claim that their usual practice is to do ‘X’ despite there being no written record of them performing that action. Similarly, a patient may have a recollection of events from one of their attendances or appointments without any notes to that effect. An expert doesn’t need to make a determination on the credibility of either party to get through this. Rather, the expert should set out that their opinion is based on the assumption of a fact, or better yet, the expert should say how their opinion would change, if at all, if a fact they rely on is not borne out in the evidence.
While this proactive approach may seem to dilute the expert’s opinion, it will go a long way in reinforcing the credibility of the expert by removing any suggestion that they are advocating for one side by ‘ignoring’ the other.
2) Experts should be willing to make concessions.
“When the facts change, I change my mind. What do you do sir?” This quote, attributed by some to the economist John Maynard Keynes, comes to my mind for this tip, which is similar to the first tip in many ways. Tell your experts to agree with the opposing view, and to be willing to concede opposing points when they are reasonable or make factual sense.
Experts are allowed to change their mind if they are presented with different facts or points of view. A standard of care expert in a medical malpractice case, whether supportive or critical of the defendant, must be willing to concede the opposing view when confronted with hypotheticals and counterfactuals.
Experts should be coached, within reason, to expect this type of confrontation in rebuttal reports and cross-examination at trial, and should be advised to resile from and concede points when appropriate.
3) Experts are not advocates.
This seems obvious, but it bears repeating and should be emphasized to any expert that a lawyer works with. Experts must be fair, objective, and non-partisan. Experts themselves do not put one side’s case forward over another – this must be left to the lawyers.
To that end, partisan or strong language in favour of one side should be avoided in expert reports and in the expert’s testimony. Experts should refrain from pedantry and nitpicking, and should leave overall judgment of behaviour or credibility to the trier of fact. A deferential and measured approach in expert reports and testimony will be received much better than an overzealous opinion.
Lawyers should sit down with their experts and discuss this at the outset of a case. Provincial rules of civil procedure on the use of expert opinion evidence (such as Ontario’s Rule 53.03 and corresponding Form 53) should not be glossed over. Someone getting paid to assist with a case will naturally want to be of assistance. Litigators must be clear with expectations and must ensure that the expert’s assistance does not stray into advocacy.
References:
[1] White Burgess Langille Inman v. Abbott and Haliburton Co., 2015 SCC 23 at paras 46-49. [2] Parliament et al v Conley and Park, 2019 ONSC 3995. [3] Ibid at paras 30-36. [4] Bruff-Murphy v. Gunawardena, 2017 ONCA 502. [5] Parliament v Conley, 2021 ONCA 261. [6] Ibid at paras 49-55. [7] R v Abbey, 1982 CanLII 25 (SCC), [1982] 2 SCR 24; See also the decision in the medical malpractice case Sommerville v Fine, 2021 ONSC 5638 at para 343 – “In my view, an expert is entitled to base their opinion on assumed facts. This does not make an expert an advocate. Also, while there was some selective quoting, I am not persuaded, on balance, that [the expert] acted as an advocate.” [8] Fortune-Ozoike v Wal-Mart Canada Corp., 2023 ONSC 421. [9] Ibid at para 106. [10] Ibid at para 110. [11] Ibid at paras 136-137. [12] Finnigan et al v Lee, 2023 ONSC 489. [13] Hasan v Trillium Health Centre Mississauga, 2022 ONSC 3988. [14] Leckie v Chaiton, 2021 ONSC 7770. [15] Hamelin v Mikkelsen et al, 2018 ONSC 2984.
Written by Joseph Ur, JSU LAW
The views and content of this blog are provided for informational purposes only, and should not be construed as legal advice.