Davis v. Ng, 2024 ONSC 5875
In personal injury litigation, the admissibility of expert evidence is often contested, particularly when it involves financial loss calculations based on estimated or incomplete data. The recent Ontario Superior Court decision in Davis v. Ng, 2024 ONSC 5875, provides valuable insight into how courts assess expert testimony in such cases.
The case involved a motor vehicle collision on October 7, 2017, in which the plaintiff, Lisa Aileen Davis, a professional server, sustained injuries that impacted her ability to earn income. As a server, a significant portion of Ms. Davis’s earnings came from tips, which she did not systematically record before or after the collision. To establish her loss of income claim, the plaintiff relied on employer records, past earnings estimates and expert testimony from a forensic accountant.
Mr. Sigsworth, an accountant and Rule 53 expert, prepared two reports, dated August 4, 2021, and July 2, 2024, calculating Ms. Davis’s past and future income loss under multiple scenarios. The first scenario assumed that her tips were equal to her base wages, while the second used her estimate of approximately $750 per week in tips for 50 weeks, plus an additional $150 on St. Patrick’s Day. His updated 2024 report accounted for new economic data and an alternative scenario in which Ms. Davis would be forced into early retirement at age 60 due to her injuries. Based on these assumptions, her estimated income loss ranged from $109,612 to $514,317.
The defendant, Wayne Ng, filed a mid-trial motion to exclude Mr. Sigsworth’s testimony, arguing that his calculations were speculative and improperly relied on the plaintiff’s self-reported estimates. Defence counsel contended that the reports lacked objective verification, such as credit card receipts or employer corroboration of tip income. He also claimed that presenting multiple damage scenarios could mislead the jury and inflate the perceived value of the claim. Furthermore, the defence argued that the expert’s methodology amounted to advocacy rather than neutral financial analysis.
Justice Kaufman rejected these arguments, dismissing the motion and allowing the expert evidence to be presented. Applying the well-established R. v. Mohan, 1994 CanLII 80 (SCC), [1994] 2 SCR 9 test for admissibility of expert evidence, the court found that Mr. Sigsworth’s testimony met the necessary criteria:
- It was relevant,
- Necessary to assist the jury,
- Provided by a qualified expert, and
- Not subject to any exclusionary rules.
Justice Kaufman emphasized that while Mr. Sigsworth’s calculations relied on the plaintiff’s estimates, this did not render the evidence inadmissible—rather, it was up to the jury to assess the validity of those underlying assumptions. The court noted that the use of hypothetical scenarios is common in expert testimony and does not inherently prejudice the defence.
Additionally, the court dismissed concerns that the reports would confuse the jury, stating that the methodology was transparent and that jurors were capable of critically evaluating the expert’s conclusions. Justice Kaufman affirmed that the defendant would have the opportunity to challenge the assumptions through cross-examination and competing evidence. Ultimately, the decision underscores the principle that expert reports do not have to be based on absolute certainty; rather, they must be based on a reasonable and transparent methodology that allows for judicial scrutiny.
This ruling highlights the complexities of proving financial losses in personal injury claims, particularly in cases involving informal or unrecorded income. It serves as a reminder that while courts will scrutinize expert reports, they will not exclude testimony solely because it involves estimates—provided the expert’s approach is methodical and within accepted accounting principles. The decision also reinforces the importance of effective cross-examination and counter-expert testimony in challenging financial assessments, rather than relying on exclusion motions to eliminate evidence from consideration.
This decision reinforces the notion that the court’s role is not to pre-emptively reject expert testimony but to allow the trier of fact to weigh its reliability and relevance in the broader context of the case.