Medical Experts play a key Role in a Personal Injury Trial but can there be too many Experts?

Posted by Injury Lawyers of Ontario on February 05, 2018

A recent trial raised the issue of whether there are limitations on the number of medical expert witnesses that can be called in a trial.  The civil action, Davies v. The Corporation of the Municipality of Clarington, involved a man who was injured while he was a passenger of a VIA Rail train that derailed in November 1999. The action addressed only the amount of appropriate damages that should be awarded, as liability was not an issue for this case.

The trial had, to date, heard evidence from the plaintiff and multiple lay witnesses, which had already consumed about 10 weeks of court time. However, the court had not yet heard from the medical experts, which was expected to require another 8 to 10 weeks due to large number witnesses for the plaintiff. The defendants sought a ruling, arguing that the plaintiff must seek leave of the court to call more than three expert witnesses, based on the ruling in Westerhof v. Gee Estate (2015). Accordingly, the judge was required to rule on the question of how many medical experts may be heard in this case.

The plaintiff intended to call expert witnesses in the area of psychology, neurology physiarty, neuropsychiatry, occupational therapy, orthopaedics, neuroradiology, as well as others in non-medical specialities. In total, 18 ‘litigation experts’ who were engaged to provide opinion evidence, as well as 18 ‘participatory experts’ (i.e. treating doctors) were scheduled to give evidence for the plaintiff. In some cases, evidence was to be presented by multiple experts in a particular field; for example, there were medical reports and clinical notes from five neurologists.  The judge noted that, while the parties in a civil action are entitled to a fair trial, they are not entitled to a trial wherein every potentially relevant piece of evidence is presented, when such evidence is repetitive of previously heard evidence.

The defendants’ position

The defendants brought a motion seeking an order to clarify that the plaintiff requires leave to present evidence from more than one expert per issue.  No real issue was taken with the plaintiff's right to call a treating doctor as a fact witness, but there were concerns involving testimony when a fact witness offers opinion evidence beyond what is normally expected from a treating doctor. In the current case, there was more than one instance where a treating doctor for the plaintiff was proffering evidence as a litigation expert.  

The defendants asserted that the fact that an expert is properly qualified and has participated in the event is not enough to render their opinion admissible.  In Westerhof, the court found that, in regards to all evidence, particularly opinion evidence, the court can exercise its gatekeeper function and exclude all or part of opinion evidence given by a participant expert or non-party expert if the evidence does not meet the test for admissibility. Further, if the opinion of such experts goes beyond the scope of an opinion formed in the course of treating or observing, for the purpose of the litigation, the court could require that these experts comply with Rule 53.03.

The criteria for admissibility of ‘opinion evidence’ is set out in R. v. Mohan, the leading authority on this question.  In order to be admissible, evidence must meet the following requirements: relevance; necessity, in terms of assisting the court to come to a determination on an issue; compliance with the rules of evidence and absent of an exclusionary rule; and a properly qualified expert.

The Ontario Evidence Act s. 12, requires ‘leave’ when a party in an action intends to call more than three witnesses to given ‘opinion evidence’. The defendants argued that the Evidence Act and the application of Mohan and Westerhof must be considered in determining whether the plaintiff must seek leave to call more than three experts in this case. 

The plaintiff’s position

The plaintiff noted that prior to the Court of Appeal decision in Westerhof, a fact witness, such as a treating physician, did not count towards the three-expert rule even if their evidence included opinion evidence.  The plaintiff referred to Hall v. Kawartha Karpet & Tile Co., (2007), where the court noted that the Evidence Act does not define the term ‘expert’ and further found that it is unreasonable to suggest that a person who was involved in the history in the normal course, such as an emergency room physician who treated the plaintiff, should be included in the three-expert maximum.

Counsel for the plaintiff also asserted that Westerhof makes a clear differentiation between a Rule 53.03 expert and a ‘participant expert’ (such as treating physician). A Rule 53.03 expert is one who has been engaged solely to offer an opinion for the purpose of the action or trial and a litigation expert generally has access to a much larger amount of information than a treating doctor and can therefore offer an opinion that provides ‘the big picture’.  Because a treating doctor or participant expert is restricted in their opinion, the plaintiff asserted that they should not count as an expert with respect to the application of s. 12 of the Evidence Act.


The judge referred to the decision in Hryniak v. Mauldin (2014), where the Supreme Court of Canada sent a strong message to trial judges that a change must occur within the Canadian civil justice system.  The Supreme Court asserted that “ensuring access to justice is the greatest challenge to the rule of law in Canada today.”  Yet, trials have become increasingly lengthy and expensive, which means that many Canadians cannot afford to go to trial when they are wronged or must defend themselves. The Court concluded that a culture shift must take place in order to create an environment that promotes timely and affordable access to justice.

The judge in the current case reviewed some of the reports by the treating doctors who the plaintiff intended to call, and concluded that some are pure fact witnesses whose evidence is within the definition of a participatory witness but others only offer opinion evidence that goes far beyond the normal role of a treating doctor.  The judge found that when a party wishes to call more than one expert in the same speciality, there is a very high onus to show why the court should allow such evidence that is essentially repetitious. 

The judge concluded that the plaintiff does not have to see leave to call any of his treating doctors, to the extent their evidence pertains to the plaintiff’s medical history, treatments provided, and the doctor’s diagnosis and prognosis.  However, if the plaintiff wishes to call a doctor to offer opinion evidence, they must seek leave to call that evidence if the plaintiff is also calling evidence from a litigation expert in the same speciality.  This means that the plaintiff and the defendants are limited to one expert per specialty unless leave to call an additional expert is first sought from the court.

The judge concluded, not only have civil trials become extremely complex and time consuming, but there are often hundreds of pages of medical records submitted as evidence when only a fraction of these pages are actually relevant and important and will be referenced in closing arguments or by the trier of fact.  While the importance of a complete evidentiary record cannot be understated, judges, lawyers and others associated with a civil trial need to ask “what are the important records that are necessary to ensure a fair and just decision”.  The judge reflected that this trial took on a life of its own, for which he bears some responsibility, but “that life now needs to be controlled” which requires plaintiff’s counsel to ask themselves which treating doctors and litigation experts are fundamental to their case.

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