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Is it Improper for Counsel to Assist an Expert Witness in the Preparation of the Expert’s Report?

Expert evidence constitutes an exception to the rule that witnesses may only testify as to facts, not opinions, and that it is the exclusive prerogative of the trier of fact to draw inferences from proven facts. The expert evidence exception operates where specialized knowledge is required to determine the implications of the facts where the trier of fact is not competent to draw the necessary inferences unaided.

The Rules of Civil Procedure (the Rules) relating to expert witnesses were updated in 2010 in response to recommendations of the Honourable Coulter Osborne contained in his report, Civil Justice Reform Project: Summary of Findings and Recommendations.[i] The amendments were intended to deal with the complaint that often experts are no more than hired guns who tailor their reports to suit the client’s needs.

First, rule 4.1.01(1) specifically addresses the duty of an expert witness:

It is the duty of every expert engaged by or on behalf of a party to provide evidence in relation to a proceeding under these rules:

(a) To provide opinion evidence that is fair, objective and non-partisan;

(b) To provide opinion evidence that is related only to matters that are within the expert’s area of expertise; and

(c) To provide such additional assistance as the court may reasonably require to determine a matter in issue.

Second, rule 53.03(2.1) provides that an expert report must contain the following information:

  1. The expert’s name, address and area of expertise.
  2. The expert’s qualifications and employment and educational experiences in his or her area of expertise.
  3. The instructions provided to the expert in relation to the proceeding.
  4. The nature of the opinion being sought and each issue in the proceeding to which the opinion relates.
  5. The expert’s opinion respecting each issue and, where there is a range of opinions given, a summary of the range and the reasons for the expert’s own opinion within that range.
  6. The expert’s reasons for his or her opinion, including,
  7. a description of the factual assumptions on which the opinion is based,
  8. a description of any research conducted by the expert that led him or her to form the opinion, and a list of every document, if any, relied on by the expert in forming the opinion.
  9. An acknowledgement of expert’s duty (Form 53) signed by the expert.

My typical practice in preparing an expert report has been to provide the retaining counsel with a draft report for discussion before completion. However, is it improper for counsel to assist an expert witness in the preparation of the expert’s report by discussing with their expert witness the content of the draft report? The answer to this question is provided by the Ontario Court of Appeal in Moore v. Getahun.[ii] In the decision, Justice Sharpe stated “…it is widely accepted that consultation between counsel and expert witnesses in preparation of Rule 53.03 reports, within certain limits, is necessary to ensure the efficient and orderly presentation of expert evidence and the timely, affordable and just resolution of claims.”

Justice Sharpe explained that the ethical and professional standards of the legal profession forbid counsel from engaging in practices that would interfere with the independence and objectivity of expert witnesses explaining that it is inappropriate for counsel to persuade or attempt to persuade experts to articulate opinions that they do not genuinely hold, and that it is of paramount importance that the expert genuinely believes the opinion that he or she articulates both in the expert report and in the witness stand.

At paragraph 63, Justice Sharpe explains the importance of consultation between the expert witness and legal counsel as follows:

Consultation and collaboration between counsel and expert witnesses is essential to ensure that the expert witness understands the duties reflected by Rule 4.1.01 and contained in the Form 53 acknowledgement of expert’s duty. Reviewing a draft report enables counsel to ensure that the report:

i. Complies with the Rules of Civil Procedure and the rules of evidence,

ii. Addresses and is restricted to the relevant issues, and

iii. Is written in a manner and style that is accessible and comprehensive.

Counsel need to ensure that the expert witness understands matters such as the difference between the legal burden of proof and scientific certainty, the need to clarify the facts and assumptions underlying the expert’s opinion, the need to confine the report to matters within the expert witness’ area of expertise and the need to avoid usurping the court’s function as the ultimate arbiter of the issues. An expert witness should never assume the role of an advocate.

[i] Ontario Ministry of the Attorney General, Civil Justice Reform Project: Summary of Findings and Recommendations, by the Honourable Coulter Osborne (Toronto, 2007), available online <>.


[ii] Moore v. Getahun 2015 ONCA 55

About Dr. Richard Shulman
Dr. Shulman is a geriatric psychiatrist at Trillium Health Partners and is an assistant professor at the University of Toronto. He is medical director of the Capacity Clinic and available for independent medical-legal capacity assessments.


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