This recent appellate decision from the Divisional Court reminds civil litigators, and jurists, that qualifying an expert is not a one-and-done exercise performed ahead of the expert giving testimony, and that it is something that needs to be continually assessed in the event new evidence comes forward to question the veracity of that qualification.
Everyone readily understands that no witness can testify as an expert unless and until the trial judge is satisfied that the proposed witness satisfies certain criteria. This is part of the trial judge’s gatekeeping function.
However, what is sometimes overlooked, as was the case here during a Small Claims Court trial before a Deputy Judge, is that this gatekeeping function is a continuing one, such that the issue of the expert’s qualification should be continually monitored throughout the trial, and if circumstances warrant, the expert should be disqualified.
In this case, the appellate court ruled that the trial judge erred in not recognizing significant problems with the expert’s qualifications as his testimony was unfolding, such as several damning admissions that included an admission that he didn’t even write his entire report, he did not have expertise in some of the aspects of the claim, and that he may have misrepresented some things in his report.
For reasons unexplained, none of the foregoing circumstances triggered the trial judge to reassess the expert’s qualifications. To make matters worse, the trial judge often prevented further enquiry by the opposing counsel when some of these matters came to light. The appellate court reasoned that it was not only inappropriate for the judge to curtail further questioning, the trial judge should have demanded further enquiry on their own initiative. Failing to do so was an abrogation of the judge’s gatekeeping function.
The trial judgment was set aside, and a new trial ordered.
For practitioners, this case is a good reminder to remain vigilant about testing the expert’s qualifications throughout the expert’s appearance in the stand, and to not get locked into the belief that once an expert is qualified, they forever remain qualified to testify as an expert. If the trial judge is dismissive, a quick reference to this case should help remind the trial judge of their ongoing gatekeeping function to continually test the veracity of the expert’s qualification throughout the trial, and where necessary disqualify the expert nunc pro tunc (a latin expression akin to “right from the beginning”).
Canadian Choice Home Services Inc. v. Sibeon, 2025 ONSC 5248 (CanLII) (Div. Ct.)
https://www.canlii.org/en/on/onscdc/doc/2025/2025onsc5248/2025onsc5248.html