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Fridays With Rogers Partners

At our weekly meeting, Athina Ionita discussed the court’s decision in Boone v. O’Kelly, 2020 ONSC 6932, which involved a ruling on expert evidence. The court determined that the defence expert’s evidence was not reliable and was, thus, inadmissible. 


The plaintiff suffered injuries during a procedure to remove a heart artery filter. He has a complicated pre-incident history, but was previously independent in almost all aspects of his daily life. Due to the subject injury, the plaintiff is confined to a wheelchair and requires constant care.

The defendants argue that the plaintiff would have found himself in the same condition he is in today because of his complicated pre-incident history. The defendants rely on the on the evidence of a physiatrist to support their “crumbling skull” argument.

The plaintiffs seek to exclude the evidence of the expert in its entirety.


Justice Beaudoin concluded that the expert’s evidence should not be admitted into trial because he failed to provide the court with fair, objective and reliable evidence, and because the evidence was more prejudicial than probative. The court comes to this conclusion by considering a number of failures on the expert’s part.

In a supplemental report, the expert opined that “in the absence of the referenced incident, Mr. Boone would have had to transition to primary wheelchair mobility for safety reasons within 5–10 years of February 2011.”

At trial, he revised his opinion down to 1-2 years. The revised opinion had not communicated to the plaintiffs prior to trial, nor was it contained in a report.

On cross-examination, the expert unsatisfactorily explained his change of opinion. He showed a pattern of stubbornly sticking to an answer until being caught in a contradiction.

Defence counsel stated that they would not rely on the expert’s new opinion and indicated that the expert was simply confused. However, Justice Beaudoin noted that the defence has not explained how this confusion would enhance the reliability of the expert’s opinion.

Another issue was the expert’s methodology in reaching his opinion, particularly his reliance on a chronology supplied to him by defence counsel.

In cross-examination, the expert insisted that he would never rely on a chronology prepared by an unknown person from the defence law firm and that his method was to confirm the information in the chronology by referring to the source documents.

This proved to be incorrect. He was challenged multiple times on specific points in his report where he appeared to rely on the chronology without referring to the source document, but he would not admit this.

Eventually, the expert wished to revisit some “inaccuracies” in his evidence and he admitted that he had “misrepresented” that he had received and reviewed certain hospital records. He also acknowledged that he relied on the narrative set out in the chronology, even though he did not know who prepared the document.

Justice Beaudoin stated that, when the expert’s reliance on the chronology was repeatedly brought to his attention, he “doubled down”, which seriously undermined his credibility.

There were a number of other problems that contributed to the expert’s evidence not being fair, objective and reliable. The expert never assessed the plaintiff in person and his opinion was limited to a review of documents curated by the defendants’ counsel. The expert was never presented with a complete picture of the plaintiff.

In addition, Justice Beaudoin found that the expert provided some evidence outside of his area of expertise and gave evasive and non-responsive answers to plainly worded questions.


The trial judge did not conclude that the expert was intentionally biased. Given that the expert’s opinion was largely based on documents that defendants’ counsel selected and sent to him, the judge found that there was an inherent bias, from the beginning.

The expert did not seek out any additional information that could have enhanced the reliability of his opinion. He also either misinterpreted or misrepresented key documents.

This was the first time the expert testified as a litigation expert. Once the expert took the stand, it quickly became apparent that he had not anticipated to have his opinion critiqued in cross-examination. He only admitted a mistake when he ran out of unsatisfactory explanations for his inconsistencies and other errors.

Justice Beaudoin excluded the expert’s evidence in its entirety. He saw no purpose in admitting the evidence since he was not able to give it any weight.