Evidence - Expert Opinion
Westerhof v. Gee Estate (Ont CA, 2015)
In this case the Court of Appeal explained the application of RCP R4.1.01 (duties of expert witnesses) and R53.03 (prior delivery of expert reports and contents thereof) to the two situations where an expert (1) had no involvement with the underlying fact history (a "litigation expert"), and where they did (a "participant expert"):
 Rule 53.03 of the Rules of Civil Procedure, R.R.O. 1990, Reg. 194, sets out the requirements for introducing the evidence of expert witnesses at trial. These appeals, which were heard together, raise related issues about to whom 53.03 applies.
 Both cases were tried following the 2010 amendments to the Rules, which were aimed at ensuring the neutrality and expertise of expert witnesses, as well as adequate disclosure of the basis for an expert’s opinion.
 Those amendments set out the overriding duty of an expert “engaged by or on behalf of a party” to provide opinion evidence “in relation to a proceeding” that is fair, neutral and non-partisan and within the expert’s area of expertise: rule 4.1.01.
 The 2010 amendments also specified certain information relating to an expert’s opinion and expertise that must be included in an expert’s report and required that the expert sign an acknowledgement of his or her duty, which identifies the party by or on behalf of whom the expert was engaged: rule 53.03(2.1), Form 53.
 Both appeals arise from claims for damages for injuries suffered in car accidents. Both cases were tried before a judge and jury. In each case, the defendant admitted liability for causing the accident, and the issues at trial related to whether the accidents caused the plaintiffs’ injuries and the quantum of damages.
 The Westerhof appeal raises the question of whether rule 53.03 applies only to experts described in rule 4.1.01 and Form 53 – experts “engaged by or on behalf of a party to provide [opinion] evidence in relation to a proceeding” (referred to in these reasons as “litigation experts”) – or whether it applies more broadly to all witnesses with special expertise who give opinion evidence. This broader group of witnesses would include, for example, treating physicians, who form opinions based on their participation in the underlying events (referred to in these reasons as “participant experts”) rather than because they were engaged by a party to the litigation to form an opinion. It would also include experts retained by a non-party to the litigation (for example, statutory accident benefits (“SABS”) insurers), who form opinions based on personal observations or examinations relating to the subject matter of the litigation for a purpose other than the litigation (referred to in these reasons as “non-party experts”).
 On appeal to the Divisional Court, Mr. Westerhof claimed that the trial judge erred in his evidentiary rulings by failing to distinguish between opinion evidence given by litigation experts and opinion evidence given by participant and non-party experts. Mr. Westerhof argued that the latter two classes of witnesses are not caught by rule 53.03.
 The Divisional Court disagreed. In dismissing Mr. Westerhof’s appeal, the Divisional Court held that the “important distinction is not in the role or involvement of the witness, but in the type of evidence sought to be admitted”: at para. 21. If the evidence at issue is opinion evidence, then compliance with rule 53.03 is required; if the evidence at issue is factual evidence, then compliance with rule 53.03 is not required.
 As I have said, I do not agree with the Divisional Court’s conclusion that the type of evidence – whether fact or opinion – is the key factor in determining to whom rule 53.03 applies.
 Instead, I conclude that a witness with special skill, knowledge, training, or experience who has not been engaged by or on behalf of a party to the litigation may give opinion evidence for the truth of its contents without complying with rule 53.03 where:
• the opinion to be given is based on the witness’s observation of or participation in the events at issue; and
• the witness formed the opinion to be given as part of the ordinary exercise of his or her skill, knowledge, training and experience while observing or participating in such events.
 Such witnesses have sometimes been referred to as “fact witnesses” because their evidence is derived from their observations of or involvement in the underlying facts. Yet, describing such witnesses as “fact witness” risks confusion because the term “fact witness” does not make clear whether the witness’s evidence must relate solely to their observations of the underlying facts or whether they may give opinion evidence admissible for its truth. I have therefore referred to such witnesses as “participant experts”.
 Similarly, I conclude that rule 53.03 does not apply to the opinion evidence of a non-party expert where the non-party expert has formed a relevant opinion based on personal observations or examinations relating to the subject matter of the litigation for a purpose other than the litigation.
 If participant experts or non-party experts also proffer opinion evidence extending beyond the limits I have described, they must comply with rule 53.03 with respect to the portion of their opinions extending beyond those limits.
 As with all evidence, and especially all opinion evidence, the court retains its gatekeeper function in relation to opinion evidence from participant experts and non-party experts. In exercising that function, a court could, if the evidence did not meet the test for admissibility, exclude all or part of the opinion evidence of a participant expert or non-party expert or rule that all or part of such evidence is not admissible for the truth of its contents. The court could also require that the participant expert or non-party expert comply with rule 53.03 if the participant or non-party expert’s opinion went beyond the scope of an opinion formed in the course of treatment or observation for purposes other than the litigation.
 Like MacLeod-Beliveau J. in McNeill, I conclude that rule 4.1.01, rule 53.03 and Form 53 are a comprehensive framework addressing a specific class of expert witnesses and expert reports. Although the words “engaged by or on behalf of a party to provide [opinion] evidence in relation to a proceeding” do not appear in rule 53.03, they appear in both rule 4.1.01 and Form 53. Rule 4.1.01 defines the expert’s duty referred to in rule 53.03(2.1)7, and rule 53.03(2.1)7 requires that Form 53 be signed. Taking account of these factors, I see no basis for concluding that rule 53.03 was intended to apply to persons other than expert witnesses “engaged by or on behalf of a party to provide [opinion] evidence in relation to a proceeding”.
 Witnesses, albeit ones with expertise, testifying to opinions formed during their involvement in a matter, do not come within this description. They are not engaged by a party to form their opinions, and they do not form their opinions for the purpose of the litigation. As such, they are not “engaged by or on behalf of a party to provide [opinion] evidence in relation to a proceeding.” A party does not “engage” an expert “to provide [opinion] evidence in relation to a proceeding” simply by calling the expert to testify about an opinion the expert has already formed.
 Similarly, the requirement in rule 53.03(2.1)3 that an expert’s report set out “the instructions provided to the expert in relation to the proceeding” makes it abundantly clear that rule 53.03 only applies to litigation experts. A party does not provide instructions to a litigation expert or a non-party expert in relation to the proceeding – that it is because these experts have already formed their opinions.
 Moreover, the conclusion that rule 53.03 applies only to experts engaged by a party to form an opinion for the purpose of the litigation reflects the prior jurisprudence and practice. As I have said, in my view, Marchand makes it clear that prior to 2010, rule 53.03 did not apply to participant experts. I see nothing in rule 53.03 reflecting an intention on the part of the Civil Rules Committee to change the status quo. Had the Civil Rules Committee intended to make a change to the jurisprudential status quo, I am confident it would have made that intention clear.