Mar 31, 2015

Expert Evidence: Ontario Court of Appeal Clarifies Requirements for Admission @ Trial

Westerhof v. Gee Estate, 2015 ONCA 206 (CanLII)

On March 26, 2015 the Ontario Court of Appeal clarified the requirements for introducing expert witness evidence at trial by deciding that Ontario's civil procedure Rule 53.03 doesn’t apply broadly to all witnesses with special expertise who give opinion evidence. The Ontario Court of Appeal’s decision in Westerhof v. Gee Estate, 2015 ONCA 206 is relevant to PEI litigation because PEI has an identical civil procedure rule (PEI Rule 53.03); while PEI courts aren’t legally obligated to follow the Ontario decision when applying the PEI rule, it will be very persuasive. Similarly, courts in NB, NS and NL aren’t obligated to follow Ontario decisions but often look to them for guidance when necessary; they don’t have an identical civil procedure rule so the impact of this decision in them isn’t obvious, but could be relevant when those courts are interpreting their respective rules.


Ontario Rule 53.03 is designed to encourage neutrality of expert witnesses. It sets out the requirements for the admission of expert testimony at trial, including the content of an expert report and the inclusion of a signed acknowledgment of the expert’s duty to the court. Failure to comply with Rule 53.03 carries the risk that the opinion evidence will be inadmissible at trial. However, there were conflicting decisions about whether Rule 53.03 applies broadly to any witness with special skill or knowledge required to give opinion evidence, such as a treating physician, or was more limited. The Ontario Court of Appeal unanimously decided it doesn’t apply broadly to all witnesses with special expertise who give opinion evidence – and particularly doesn’t apply to:


  • a witness with special skill, knowledge, training or experience who hasn’t been engaged by or on behalf of a party where that opinion is: based on the witness’s observation of or participation in the events at issue; and the witness formed that opinion as part of the ordinary exercise of her skill, knowledge, training and experience while observing or participating in the events at issue


  • the opinion evidence of a non-party expert where she’s 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. 


Read the Ontario Court of Appeal’s decision in Westerhof v. Gee Estate, 2015 ONCA 206 here. 

Please contact your McInnes Cooper lawyer or any member of our McInnes Cooper Litigation Team or our Insurance Defence Team to discuss this topic or any other legal issue.

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