Ontario’s Court of Appeal has reaffirmed that trial judges have significant discretion to control expert evidence in jury trials, and that excluding part of an expert’s testing will not, by itself, justify a new trial.
The Case in Brief
In Pederson v. Forget, 2026 ONCA 118, the plaintiff was an insurance adjuster who alleged she slipped and fell on the wooden stairs inside the defendants’ home. She claimed the top step felt “like ice” and argued that an improper cleaning product made the stairs dangerously slippery. The homeowners denied negligence, saying they used an appropriate floor cleaner, had not used Pledge, and that their stairs were not unsafe.
At trial, both parties called engineering experts to address slip resistance. The plaintiff’s expert had conducted several rounds of testing, including early tests on his own stairs and later tests at the defendants’ home. After voir dire, the trial judge qualified him as an expert but refused to admit his first set of tests because the conditions differed too much from those at the actual accident scene.
The jury ultimately found the defendants were not negligent and dismissed the action. The plaintiff appealed, arguing that excluding the first test was a legal error that led to a miscarriage of justice.
What the Court of Appeal Held
The Court of Appeal dismissed the appeal and left the jury’s defence verdict in place. In doing so, it emphasized that:
- Trial judges must perform a gatekeeping role for expert evidence, especially in jury trials, and may exclude testing that does not closely reflect the real accident conditions or has limited value.
- It is not enough, on appeal, to show that a piece of evidence might have been admissible. The appellant must show that excluding it could realistically have changed the outcome of the trial.
- In this case, the jury could reasonably decide liability based on the competing evidence about what product was used, whether the stairs were actually slippery, and whose account they believed, without needing the excluded testing.
Takeaway for Occupiers’ Liability Litigation
Pederson v. Forget serves as a reminder that trial judges have wide latitude to shape expert evidence, particularly when testing conditions stray from the actual facts. Litigants must ensure that expert work is carefully tailored to the incident circumstances and be prepared to succeed (or defend) on the strength of lay testimony and credibility findings when technical evidence is narrowed.
Flaherty McCarthy LLP follows these developing decisions closely to help clients navigate the strategic use of expert evidence in personal injury and occupiers’ liability cases across Ontario.
