Executive Summary: Key Legal and Evidentiary Issues

• Timing and validity of expert reports filed after the Finish Date, and whether court leave is mandatory despite party consent.
• Interaction between Rule 55 (Expert Opinion) and the Finish Date regime, including the consequences of late disclosure for fairness and trial readiness.
• Scope of the court’s discretion under Rule 51.03(1)(d) to exclude or admit late expert opinion where exclusion would be “unjust.”
• Extent of the procedural rights triggered by late expert reports, including rebuttal rights, written questions, and notice of cross-examination.
• Interpretation of Rule 55.13 on when experts may or must testify orally, and how admissions or silence on qualifications and admissibility operate.
• Appropriate remedial response where new medical information causes material changes in expert opinion close to trial without formal leave having been sought.

Background and procedural context
The decision in Lehan v. Awad Estate, 2026 NSSC 5, arises in the Supreme Court of Nova Scotia on a motion dealing with late expert evidence and its procedural consequences in a civil action. The plaintiff, Claire Lehan, has sued the Estate of Mahmoud Abdul Awad, with the matter set for a ten-day trial beginning on February 17, 2025, and a Finish Date of November 3, 2025. The case is managed under Nova Scotia’s civil procedure regime, in which the Finish Date is a central milestone by which parties must have completed all pre-trial procedures and complied with various disclosure and evidentiary obligations, including the exchange of expert reports. The decision is written by Justice John A. Keith following a case-management hearing held on December 19, 2025, convened specifically to address issues that arose because both sides served and filed expert neurologist reports close to or after the Finish Date, without formally seeking leave, even though Court Administration accepted the filings.

Expert evidence and chronology of reports
The evidentiary context is driven by duelling neurologists. On January 30, 2024, the defendant filed an expert report from Dr. David King, neurologist, dated January 18, 2024. At a Date Assignment Conference held on February 2, 2024, the court fixed a ten-day trial for February 17, 2025 and set the Finish Date at November 3, 2025. On April 28, 2025, the plaintiff filed an expert report by Dr. Sarah Mitchell, neurologist, dated September 17, 2019 with an addendum dated December 11, 2019. Under Rule 55.03(1), all independent expert reports were to be filed no later than June 3, 2025, six months before the Finish Date; neither party sought leave to change the Finish Date or the default expert deadlines. On August 27, 2025, the defendant provided the plaintiff with an unfiled copy of a supplemental report from Dr. King, erroneously dated July 23, 2024. That supplemental report was more than three months late vis-à-vis the June 3, 2025 expert deadline and was itself delivered less than three months before the November 3, 2025 Finish Date, even though other parties are afforded three months under the Rules to respond with rebuttal reports. The parties agreed that Dr. King’s supplemental report contained new and material information that had only been disclosed after his original report and that this new information prompted him to reconsider and alter his opinions. On September 10, 2025, the defendant filed Dr. King’s supplemental report (still bearing the erroneous July 23, 2024 date). As of the Finish Date, November 3, 2025, neither party had formally admitted or contested the qualifications of the other party’s expert, but both had notified the other of their intention to cross-examine the opposing neurologist at trial. On that same Finish Date, the defendant filed an amended version of Dr. King’s supplemental report, this time solely to correct the completion date from July 23, 2024 to the actual date of August 1, 2025. The defendant maintained that this corrected supplemental report was otherwise identical in substance to what had been filed on September 10, 2025, and again did not seek leave; Court Administration nevertheless accepted it. On November 18, 2025, the plaintiff wrote to the Court to raise concerns regarding Dr. King’s addendum, but indicated that the plaintiff would consent to Dr. King’s additional material, provided the plaintiff was permitted to file a rebuttal report from Dr. Mitchell. On December 9, 2025, the plaintiff filed Dr. Mitchell’s rebuttal report dated December 8, 2025, without seeking leave; Court Administration again accepted the filing. The net result was that Dr. King’s supplemental and corrected reports were filed on or close to the Finish Date, and Dr. Mitchell’s rebuttal was filed after the Finish Date and within roughly two months of trial.

Civil Procedure Rules and expert opinion framework
The court situates this dispute within the broader framework governing expert evidence in Nova Scotia, especially Rule 55 – Expert Opinion, and its connection to the Finish Date. Justice Keith emphasizes that the trier of fact generally draws its own inferences from admissible evidence and does not ordinarily rely on witness opinions, save for recognized exceptions such as expert opinion, which assists the court on matters outside the experience of an ordinary person. The decision cites leading authority such as R v Mohan, R v Abbey and White Burgess Langille Inman v. Abbott and Haliburton Co. on the role of experts and the dangers of “mystique of science” overwhelming the fact-finding process. Rule 55 is designed to balance the usefulness of expert testimony with the risks of undue influence, surprise, delay, and disproportionate cost and complexity in civil litigation. Two core propositions animate the Rule: an expert’s primary duty is to the court (not to the party who retained them), and, except in exceptional circumstances, an expert’s direct evidence is contained entirely within a written report, which must be served and filed well before trial, including for rebuttal experts. This written-first approach is tied to Rule 1.01’s overarching goal of a “just, speedy, and inexpensive” determination of every proceeding and the proportionality principles articulated by the Supreme Court of Canada in Hryniak v. Mauldin.

Deadlines, Finish Date, and late expert reports
Justice Keith explains that the Finish Date, set at the Date Assignment Conference, is a central organizing milestone for a civil action: parties are deemed to have completed all pre-trial steps by that date, and various obligations—witness lists, admissions, notice of certain evidence—are tied to it. Expert evidence deadlines are also anchored to the Finish Date. Under the default rules, independent expert reports must be filed at least six months before the Finish Date, and rebuttal reports are due within three months after an initial expert report is received. Once the Finish Date is fixed, it cannot be unilaterally changed; accordingly, neither can the associated expert deadlines be recalculated without court leave. At the same time, the Rules recognize that new, material information may emerge, particularly in personal injury matters, and impose a continuing obligation on experts (and rebuttal experts) to notify parties of any material change in opinion or newly significant facts as soon as possible. Prior to the Finish Date, parties may, by mutual consent, accept late expert reports beyond the default or judge-imposed deadlines, but if there is not unanimous consent, leave of the Court is required. After the Finish Date, the analysis changes: parties cannot control or adjust the process simply by agreement. Justice Keith holds that once the Finish Date has passed, leave of the Court is required in order for any party to rely on an expert opinion report filed thereafter, including rebuttal opinions, because such reports are necessarily “not disclosed in accordance with Rule 55” and trigger Rule 51.03(1)(d)’s mandatory exclusion of undisclosed opinion evidence unless its exclusion would be unjust. Late filing also prejudices the receiving party, who must absorb and potentially respond to technical evidence in the compressed pre-trial period when all steps should already be complete, and may undermine trial dates because a suite of interlocking procedural rights—written questions, rebuttal rights, challenges to conformity under Rule 55.10, notice concerning qualifications, admissibility, and cross-examination—are all pegged to deadlines that are assumed to expire by the Finish Date. Accordingly, the judge sets out a non-exhaustive list of factors relevant to whether it would be “unjust to exclude” a late expert report, including the nature of the new opinion, whether it could reasonably have been addressed earlier, the timing and explanation for the change, its importance to the issues in dispute, the degree of prejudice and potential impact on trial dates, and whether consent has been given.

Controls on calling experts and cross-examination
The judgment also clarifies how Rule 55.13 governs when an expert may be called to give oral evidence at trial. Generally, where qualifications and admissibility are admitted, an expert need not be called to “prove” their report; the report is simply marked as an exhibit, subject to cross-examination if proper notice has been given. A party must determine by the Finish Date whether it admits or contests an expert’s qualifications or the admissibility of the report. If it does neither, the Rule is interpreted to presume that both qualifications and admissibility are admitted, as the Rules do not allow a party to leave that election in limbo indefinitely. If either is contested, the expert must be called and examined on voir dire, and any further direct examination is tightly limited. The decision underscores that a party receiving a report has a right to cross-examine the expert at trial by giving notice prior to the Finish Date; the party who filed the report is then expected to call the expert for that purpose, and failure to do so risks exclusion of the report. The judge also discusses the narrow residual power under Rule 55.13(2)(c), allowing a court to grant leave for direct oral testimony beyond the written report only where “justice requires,” a threshold that connotes necessity rather than mere convenience.

Application of Rule 55 to the neurologists’ reports
Applying these principles, Justice Keith notes that Dr. King’s supplemental report was provided and then filed close to the Finish Date, and his corrected supplemental report was formally filed on the Finish Date itself. Dr. Mitchell’s rebuttal report followed after the Finish Date, less than two months before trial. The plaintiff was prepared to consent to Dr. King’s qualifications and the admissibility of his supplemental report on three conditions: that Dr. Mitchell’s qualifications and the admissibility of her rebuttal report be admitted, and that both experts be called at trial to be cross-examined on all of their respective reports. The judge holds that, in these circumstances, the defendant was required to seek leave to introduce Dr. King’s supplemental and corrected reports, and the plaintiff, likewise, needed leave to file and rely on Dr. Mitchell’s rebuttal report after the Finish Date. The court then assesses whether such leave should be granted. All parties accept that Dr. King’s supplemental report reflects a material change in his opinion based on information that arose after his original report and that it meets the content requirements of the Rules. All parties also accept that Dr. Mitchell’s rebuttal report is properly confined to rebutting Dr. King and is compliant with Rule 55. No one contests the qualifications of either neurologist, and no one challenges the admissibility of any of their reports, subject to the usual right of cross-examination. The parties confirm that both Dr. King and Dr. Mitchell will be called at trial solely for cross-examination on their reports. Crucially, no party alleges undue delay or suggests the scheduled trial dates must be adjourned as a result of the late filing.

Outcome and implications for the parties
In light of these “uniquely collaborative circumstances,” Justice Keith concludes that leave from the Court is indeed required whenever a party seeks to file any expert opinion report, including rebuttal reports, after the Finish Date, regardless of party consent. In the specific case of Lehan v. Awad Estate, the Court exercises its discretion to grant leave nunc pro tunc for both sides: Dr. King’s supplemental and corrected reports are allowed to stand, and Dr. Mitchell’s rebuttal report is likewise accepted. Both experts will be available for cross-examination at trial, and the existing dates remain intact. Procedurally, both the plaintiff and the defendant achieve what they sought—permission to rely on their late-filed expert material—so there is no single “successful party” on this motion in any conventional sense. The decision does not resolve liability or quantum in the underlying personal injury action, and it contains no order granting damages, costs, or other monetary relief; accordingly, the total amount of any monetary award or costs in favour of any party cannot be determined from this decision.