September 25, 2024 – Admitting Expert Evidence

“The threshold requirements for expert evidence admissibility are set out in R. v. Mohan, 1994 CanLII 80 (SCC) (relevance, necessity, absence of an exclusionary Rule and a properly qualified expert). Only the last requirement is disputed in this case. In White Burgess Langille Inman v. Abbott and Haliburton Co., 2015 SCC 23, the admissibility test evolved to require a two-step analysis; first, the court must apply the Mohan criteria then, second, the court must exercise a discretionary function, balancing the potential risks and benefits of admitting the evidence.  At this second, or “gatekeeping”, stage relevance, necessity, reliability, and absence of bias are helpful factors “in weighing the overall competing considerations in admitting the evidence.”: White Burgess, at para. 54.

In Aldush v. Alani, 2021 ONSC 6410, a parenting case in which the court needed assistance in the understanding of Sharia law, Smith J. outlined the expectations of a proposed expert and the non-exhaustive factors going to the issue of qualifications (citations omitted).

[24]           A properly qualified expert must be able to provide fair, objective and non-partisan assistance to the Court.  The expert’s opinion must be impartial, independent, and absent of any bias.  In terms of independence, the expert’s opinion must be the product of independent and uninfluenced judgment: White Burgess Langille Inman.

[25]           To be found as a properly qualified expert, the Court must be satisfied that the expert has “acquired special or particular knowledge through study or experience in respect of the matters on which he or she undertakes to testify”: R. v. Mohan.

[26]           The words “properly qualified” does not only mean “judicially qualified” but also refers to academic and experiential credentials, as well as registration with a governing body regarding the expertise: Children’s Aid Society of Algoma v. F.M.

[27]           Factors that can assist the Court in determining if the tendered witness is qualified includes the expert’s formal education, professional qualifications, membership and participation in professional associations, attendance at courses or seminars in the subject matter, experience, teaching and writing in the proposed area, and previous qualification to give opinion evidence: R. v. Pham.

As pointed out in Dulong v. Merrill Lynch Canada Inc., (2006), 80 O.R. 3d 378it does not matter how the witness acquired the “special” or “peculiar” knowledge about the matter on which they have undertaken to testify so long as they can demonstrate they have acquired that knowledge. As Ducharme J. noted,

[21] When assessing the qualifications of a proposed expert, trial judges regularly consider factors such as the proposed witness’s professional qualifications, her actual experience, her participation or membership in professional associations, the nature and extent of her publications, her involvement in teaching, her involvement in courses or conferences in the field and her efforts to keep current with the literature in the field and whether or not the witness has previously been qualified to testify as an expert in the area.”

          Ierullo v. Ierullo, 2023 ONSC 5390 (CanLII) at 3-5

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