The decision of Justice Stinson on appeal from the master in  Edwards v. McCarthy, 2019 ONSC 3925 (CANLII) addresses the issue regarding the timing of the production of all communications between counsel and an expert. In particular, whether a defendant, by disclosing a Rule 53.03 compliant expert’s report, was obligated to disclose the letter of instruction and other foundational documents prior to trial and before a decision was made to call the expert as a witness.


In this solicitor’s negligence action, the defendant had undertaken at his examination for discovery to provide the disclosure required under the Rules regarding any experts retained and their opinion. The defendant subsequently served an expert report which addressed the issue of standard of care. Further to the defendant’s undertaking, counsel for the plaintiff requested the following documents, which were refused:

(a) production of documents or disclosure of information that demonstrate the instructions on which the expert proceeded;

(b) production of documents or disclosure of information that demonstrate the assumptions the expert was asked to make;

(c) production of documents or disclosure of information that evidence the facts that the expert relied upon;

(d) documents and materials given to the expert by the litigant or the litigant’s counsel;

(e) all prior drafts of the expert’s report; and

(f) all correspondence as between the expert and his instructing counsel which contain foundational information.

The Master’s Decision

At the motion, neither party disagreed with the general proposition that foundational information of the nature requested by the plaintiff must be disclosed for any expert upon whom a party intends to rely at trial.

The disagreement was when such information ought to be disclosed. The defendant was of the position that it is only after a decision has been made to call the expert as a witness at trial that the information needs to be disclosed. The plaintiff, on the other hand, argued that the information should be disclosed at the pre-trial stage because the defendant chose to formally serve the  expert report, thereby waiving litigation privilege in relation to the requested documents.

The Master agreed with the plaintiff’s position in requesting items (a) to (d), listed above. The Master concluded that serving a report at the discovery stage triggers the opposing party’s right to obtain the foundational information. She reasoned that the foundational information becomes available because the serving party had “flagged” its intention to rely on an expert at trial, thereby giving an implied waiver of the litigation privilege that would have otherwise protected the report and its related documents.

The Appeal Decision

Justice Stinson of the Ontario Superior Court of Justice held that the Master erred. He reasoned that the defendant had merely complied with Rule 53.03 in order to satisfy the procedural pre-conditions to be permitted to call the expert as a trial witness. By simply serving the expert report, it does not automatically follow that the defence expert will testify at trial. He further noted that whether to call an expert at trial is generally a decision that can only be made by defence counsel once the plaintiff’s case is closed.

In his reasons, Justice Stinson also referred to the decision of Maxrelco Immeubles Inc. v. Jim Pattison Industries Ltd., 2017 ONSC 5826 (CANLII), a case that is an all fours with the present one. In that case, Justice O’Bonsawin held that where the expert report contains the instructions from counsel, as required by Rules 53.03(2.1), 3, and 4, the letter of instruction remains covered by litigation privilege and need not be produced. Notably, Justice Stinson pointed out that in the present case, as in Maxrelco, the report contained all the foundational information prescribed by Rule 53.03(2.1), such as the instructions provided to the expert in relation to the proceeding and the nature of the opinion being sought. Justice Stinson also noted that there was no evidence that might support a reasonable suspicion that counsel improperly influenced the expert, and as such litigation privilege continued to attach to the communications and documents in question.


Serving an expert report that complies with Rule 53.03 at the discovery stage, in order to satisfy the procedural pre-conditions to be permitted to call the expert at trial, will not waive litigation privilege. The foundational documents and information will remain protected by litigation privilege until it is clear that the expert is going to testify at trial.   However, caution should be taken to ensure that the information prescribed by Rule 53.03(2.1) is included in an expert’s report. Failing to do so may bolster’s a plaintiff’s claim that there has been inappropriate influence on an expert, potentially removing litigation privilege with respect to the foundational documents.  Although this decision dealt with a defense expert on the issue of a solicitor’s negligence, the same principles and rules should apply to medical experts. The immediate application of this decision to other forums, such as the Licence Appeal Tribunal, is not clear. However this will be a decision that should be relied upon by insurers whenever plaintiffs or applicants seek foundational documents for expert reports before a decision has been made to call that expert as a witness.

Spencer Wong is a member of the Licence Appeal Tribunal practice group and author of this blog. If you have a questions about this decision or a similar file, please contact Spencer at 647-427-3340