In will challenges, the evidence of doctors and other medical experts often plays a central role where the testamentary capacity of the testator is in issue. A case can turn on the report of a capacity assessor or a letter from a doctor regarding the mental state of the testator at the relevant time.
The Rules of Civil Procedure provide some guidance with respect to expert evidence at trial. One goal of these provisions is to ensure that experts are qualified to give opinions in the subject area for which they are called to give evidence. Another is to combat the bias that may arise where experts are recruited by one side or the other in an adversarial system.
In Ontario, Rule 4.1.01 of the Rules of Civil Procedure will apply to the evidence of experts. This Rule sets out that experts engaged by or on behalf of a party to give evidence in relation to a proceeding have a duty (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. Further, Rule 4.1.01(2) sets out that these duties prevail over any obligation owed by the expert to the party engaging him or her.
The use of expert evidence at trial is governed by Rule 53.03. If an expert is to be called at trial, in order to avoid surprises, the Rule sets out a timetable for exchanging expert reports, beginning before the pre-trial conference. The Rule also requires certain information to be included in the expert’s report, including the expert’s qualifications and experience, the instructions provided to the expert, an explanation of the nature of the opinion and to what issues it relates, the assumptions, facts, research, and documents upon which the opinion is based, and, of course, the expert’s opinion and an explanation of it. The expert must also sign an Acknowledgment of Expert’s Duty (Form 53), in which he or she must acknowledge that his or her obligations to the court to provide objective, non-partisan evidence within his or her area of expertise, and that these obligations trump other obligations owed to any party.
When the expert is a physician who had treated the testator, he or she may be called as witness for the purpose of giving factual evidence about the state of the testator at the time of treatment. According to the recent case of Westerhof v. Gee (Estate), where treating physicians are called to testify, they may give factual evidence, such as their observations of the patient and the treatment provided, without falling under Rule 53.03. However, if the treating physician is asked to offer an opinion, the procedures in Rule 53.03 must be followed.
The case also addresses the argument that, for a physician, acknowledging that his or her obligations to the court prevail over obligations to the patient conflicts with the Hippocratic oath, which requires the doctor to put the patient’s interests first. Lederer J. notes that in advocating for their patients, doctors should not be free from maintaining their objectivity or free to offer opinions outside their areas of expertise. In this sense, the Hippocratic oath does not inherently run contrary to the obligations of the physician as an expert witness at all.
While Westerhof v. Gee (Estate) deals with a personal injury and evidence as to the nature, extent and cause of the injury, many of the principles are applicable to medical evidence in litigation where the mental state of an individual is an issue. It is a good case to read if you want to become an expert on experts.