The disclosure of expert reports and their supporting data is a widely litigated area.

The jurisprudence in all Canadian jurisdictions is fairly consistent that a party is entitled to the foundational or underlying material of an opposing party's expert report at some point. As stated by the Supreme Court, "the opposing party must be given access to the foundation of [expert] opinions to test them adequately".1 This disclosure requirement applies even to factual underpinnings that the expert had in its possession but did not actually use in creating its ultimate report.2

The dividing issue when it comes to the factual underpinnings of expert reports is when they must be produced. Some courts and jurisdictions consider production required when an expert report is served, for others it is only when the report is entered at trial or the expert is called to testify.

The Rule

Recent Alberta jurisprudence generally only requires production of underlying materials to expert reports once the report has been entered at trial or the expert has been called to testify.

This is a departure from previous case law and from the jurisprudence in most other jurisdictions.3 Older Alberta jurisprudence under the previous Alberta Rules of Court generally held that once an expert report is served, privilege is waived and the opposing parties are entitled to the underlying materials.

Under the previous rule, Rule 218.1, the party was required to serve a copy of the expert report including "the substance of his opinion". In a 1985 decision, the Alberta Court of Queen's Bench concluded that the substance of the opinion includes not only the opinion but the factual information upon which that opinion is based.4

The Alberta Court of Queen's Bench eventually diverged from this opinion in 2005 in Chernetz v Eagle Copters Ltd,5 preferring upholding privilege over trial efficiency. The Court held that privilege is not waived over the underlying materials until the expert report is entered, or the expert is called, at trial. This also means that if the expert report is not ultimately used at trial, privilege over the foundational materials is never waived.

Despite a 2008 Alberta Court of Appeal6 decision emphasizing the importance of early production of the information underlying expert reports, new Alberta cases since the introduction of the 2010 Alberta Rules of Court have generally followed the Chernetz line of reasoning, holding that privilege is not waived over the underlying materials until the report is entered or the expert is called at trial.

For example, in Grammer v Langpap,7 Master Smart dealt with an application for the production of underlying documents to an expert report that was voluntarily disclosed to them by the plaintiff.

In conclusion, Master Smart said:

Despite the laudable objectives of the foundational rules when noting the limited ability to question experts before trial under the rules and absent clear language in the rules altering litigation privilege historically afforded to litigants, I'm not prepared to order the production of the experts underlying documents in these circumstances".8

Master Smart applied Chernetz and found that litigation privilege continued to exist for those documents not compelled to be disclosed until trial. Privilege therefore continues to win the day over trial efficiency in Alberta jurisprudence.

The Way Around

There is however a "go-around" in the form of Rule 5.37 for the questioning of experts before trial.

Rule 5.37 allows a party to question an opposing party's witness prior to trial by agreement or in "exceptional circumstances". Where a successful application is brought, the party can question the opposing expert on their report and all underlying materials, which are required to be disclosed at that time.

This "exceptional circumstances" test has been applied in applications seeking the production of the foundational materials to an expert report, independent of an application to question the expert.9 This potentially allows a party to gain access to the foundational materials well in advance of trial. The difficulty is that the court will only grant such an application in "exceptional circumstances"; however, one case shows that efficiency considerations can be enough to satisfy this requirement.

In M (BJ) v M (SL),10 the Court dealt with an application under Rule 5.37 for questioning an expert before trial. The Court found that exceptional circumstances existed because this was a particularly complicated family matter and the pre-trial questioning "may well result in a reduction in the time and complexity of the forthcoming trial".11 The judge also thought that the questioning might reduce the number of experts or even lead to settlement.

The Court found that granting the application "with a view to achieving some or all of these results is consonant with the foundational rules set forth in the Rules".12 The Court therefore allowed the questioning of the expert approximately three months before trial, including requiring that the opposing party produce the documents reviewed in preparing the report.

Of note, Rule 8.4(3) of the Alberta Rules requires that parties requesting a trial date certify that expert reports have been exchanged and that the questioning of experts is complete. There is, therefore, a general expectation that a Rule 5.37 application will be brought early in the litigation process, before the matter is set for trial.


If you are involved in litigation involving experts, you will be entitled to the foundational material of any opposing party's expert report so that you and your expert(s) can adequately test the validity of that report. Under recent Alberta jurisprudence, this entitlement does not arise until the expert report is entered at trial or the expert is called to testify. This leaves little time for testing.

One potential route to earlier production of these factual underpinnings is through Rule 5.37. Where "exceptional circumstances" exist, the Court may order the production of the underlying materials earlier in the litigation process. While "exceptional" on its face is a difficult bar to meet, the Court has previously granted such an order based entirely on efficiency considerations as codified in the Alberta Rules of Court. Gaining early access to these materials may be very helpful to your case, whether for settlement discussions or informing your own expert's report


1. R v Stone, [1999] 2 SCR 290 at para 99.

2. Lamont Health Care Centre v Delnor Construction Ltd, 2002 ABQB 1125.

3. For example, in Ontario the foundational materials must be produced when an expert report is served in accordance with Rule 53.03, in other words at a minimum of 90 days before a pre-trial conference: Moore v Getahun, 2015 ONCA 55; Galea v Best Water Limited, 2019 ONSC 7213.

4. Commonwealth Construction Co v Syncrude Canada Ltd (1985), 64 AR 132 at para 22 (QB).

5. 2005 ABQB 712 [Chernetz].

6. Deloitte & Touche LLP v Institute of Chartered Accountants of Alberta, 2008 ABCA 162.

7. 2014 ABQB 74 [Grammer].

8. Ibid at para 10.

9. See e.g., Grammer, ibid.

10. 2012 ABQB 731.

11. Ibid at para 29.

12. Ibid.

The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.