Expert Evidence – The New Normal

The Verdict – Issue 169 / Summer 2021

The Verdict issue 169

This is the seventh article in our 8-part series on medical malpractice litigation published in the Verdict law journal. In this article Paul McGivern reviews how the use of experts at trial has evolved over the years, and discusses recent developments in the law.

  • The Doctor-Patient Relationship and Duty of Care(Verdict Issue 163 – Winter 2019)
  • Consent (the Verdict Issue 164 – Spring 2020)
  • Standard of Care (the Verdict Issue 165 – Summer 2020)
  • Defences to a Claim of a Breach of the Standard of Care (the Verdict Issue 166 – Fall 2020)
  • Causation – Basic Principles (the Verdict Issue 167 – Winter 2020)
  • Causation – Application (the Verdict Issue 168 – Spring 2021)
  • Expert Evidence
  • Disclosure of Errors

In previous articles, we outlined the essential criteria in a medical negligence action including the requirements to prove a duty of care owed by the defendant to the patient, a breach of the standard of care on the part of the defendant and a causal link between the breach of the standard of care and the plaintiff’s injuries and the basic rules for establishing and applying causation. In this article, we will highlight both common law and statutory rules relating to the admissibility of expert evidence and identify issues counsel need to deal with in leading expert evidence at trial.

It is hard to remember a time when expert evidence was not an integral part of almost every case. Over the decades counsel have found that experts were an important part of proving our cases, indeed, an essential part in most cases. The last thing any lawyer wanted to see was a judgment dismissing our case on the basis that no expert evidence was led to prove a critical aspect of our case. Expert evidence was persuasive and compelling, all the more so when the expert was willing to become part of “the team”, advocating on behalf of our clients. The use of expert evidence became ubiquitous. The judiciary largely went along with this, probably to avoid the risk of a new trial if the evidence was rejected (see, for example, Morrison v Hicks (1991) 80 DLR (4th) 659 (BCCA) where the court ordered a new trial after the trial judge refused to allow further evidence on a point that had already been canvassed in other evidence at trial).

This led to a number of abuses, most particularly the phenomenon of the “expert as advocate”.

Our courts have struggled to reign in this problem with limited success. Starting in 2010, the legislature amended the Rules to strengthen the requirements for the admissibility of expert evidence. In 2014 and again in 2015, the Supreme Court of Canada weighed in to address the issue in judgements which have given the courts new impetus to control the type and manner of expert evidence and to reject evidence which does not meet appropriate criteria.

The purpose of this paper is to highlight both common law and statutory rules relating to the admissibility of expert evidence and to deal with some of the more prominent issues counsel need to deal with in assessing whether and how to lead expert evidence.

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Paul McGivern K.C.


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