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What is the Test of Admissibility?

In this blog, we will discuss the recent court decision: Morris et al. v. Prince et al., 2022 ONSC 1291. In this voir dire, the judge ruled the defense expert life care planner’s evidence inadmissible due to his “failure to be impartial and unbiased.”

In the subject case, the Plaintiff was a pedestrian who was struck by a motor vehicle driven by the Defendant. As a result of the MVA, the Plaintiff suffered a traumatic brain injury.

An expert in life care planning and vocational rehabilitation was retained by the Defendant to provide the court with evidence regarding the Plaintiff’s future care needs and vocational capabilities.

In this case, the Plaintiff seeks a ruling to declare the evidence of the defense expert life care planner inadmissible because it does not meet the Mohan test for admissibility.

The judge determined the admissibility of the defense expert’s proposed evidence using the Mohan criteria which state that:

“Admissibility of expert evidence has to be (a) relevant (b) necessary in assisting the trier of fact, (c) does not fall within any exclusionary rule and (d) is given by a properly qualified expert.”

Justice Mitchell determined that the defense expert was not a properly qualified expert due to his lack of impartiality and independence as an expert witness.

According to Justice Mitchell, a proposed expert’s impartiality is one of the basic standards for the admissibility of expert evidence.

He further states that expert witnesses have a “special duty to the court to provide fair, objective and non-partisan assistance [and] if they are unable or unwilling to comply with this duty, they are unqualified to give their opinion and should not be permitted to do so.”

The defense expert life care planner erred in overstepping and aligning himself with the Defendant who is also his client.

Justice Mitchell determined that the Defendant’s life care planner assumed the role of an advocate for the Defendant’s position from the outset of his retainer and therefore is unable to provide fair objective evidence in this case.

In the defense expert’s report, he highlighted the positive information about the Platintiff and downplayed injuries and capabilities. The positive information highlighted was not relevant to the assessment of the Plaintiff’s future care needs.

To highlight the positives and downplay the negatives regardless of evidence is, in the judge’s view, an indication of bias in favor of the Defendant and demonstrates that the defense expert does not understand his role and duty to the Court to remain impartial and free of bias.

In addition, rather than meeting with the Plaintiff to conduct an independent assessment of his vocational abilities and his ability to perform activities of daily living (which the defense expert admitted was industry best practice), he relied entirely on reports, interviews and assessments conducted by others.

One-half of the defense expert’s 60-page report was a summary of the information he reviewed. The defense expert did not request, let alone conduct, an in-person, virtual or telephone interview with the Plaintiff.

Justice Mitchell opines that this strongly suggests a lack of independence in his approach to the assessment of the issue.

Justice Mitchell further states the defense expert has the responsibility to provide the Court with his opinion as to the realistic future needs of the Plaintiff. His optimism for the Plaintiff’s future should have played no part in his assessment of future care needs.

To conclude, life care planners should bear in mind the importance of providing unbiased, impartial and independent evidence in court, as these are basic standards for the admissibility of expert opinion and evidence.

To be precise, the expert’s opinion must be impartial in the sense that it reflects an objective assessment of the question at hand. It should also be independent in the sense that it must be a product of the expert’s independent judgment, uninfluenced by who retained him/her, or the outcome of the litigation.


Bartlett, Danielle. “Morris Et Al. v. Prince Et Al., 2022 ONSC 1291.” Ontario Trial Lawyers Association Blog, 26 May 2022,