On the morning of November 21, 2025, Prof. Hamish Stewart from the University of Toronto Faculty of Law delivered a lecture titled “Canada’s Evidence Law Reform” as part of the PKU Law School’s Global & Comparative Law Series. The event was chaired by Prof. Wu Hongqi of PKULS.

This article summarizes the key points of the lecture.

Hamish Stewart:

In his opening remarks, Prof. Wu noted that Chinese students are often familiar with U.S. and U.K. evidence law but less so with Canada’s. Yet the common law system is not monolithic—Canada, the U.S., and the U.K. have pursued distinct paths in evidence reform since the mid-1960s. Understanding Canada’s approach reveals the diversity of solutions within the common law tradition.

My talk covers four sections: a brief introduction, an overview of common law trial procedure, traditional evidence rules, and Canada’s reforms. As Prof. Wu indicated, I will focus on the last.

Common law evidence rules were largely uniform 70–80 years ago, but have since diverged. Key features of common law trials include:

1. Adversarial nature: Parties control case presentation, evidence, and arguments; judges and juries do not investigate.

2. Oral tradition: Witnesses testify in person, with juries assessing credibility through demeanor—though I question its reliability.

Evidence must be introduced through witnesses, even documents, to avoid hearsay issues. This contrasts with civil law systems relying on written evidence. Recent cases, such as those involving veiled witnesses or mask-wearing during COVID-19, have challenged the emphasis on demeanor observation.

Judges determine admissibility: if evidence is excluded, juries must ignore it. Evidence rules balance multiple goals: accuracy, fairness, efficiency, and respect for witnesses. The core principle is “probative value outweighs prejudicial effect.”

The hearsay rule is particularly complex. It excludes out-of-court statements offered for their truth, as the declarant cannot be cross-examined. Traditional exceptions were rigid; for example, in Myers(U.K.) and Williams(Canada), reliable evidence was excluded for lacking an exception. This rigidity spurred reforms.

Reforms varied: the U.K. legislated changes; the U.S. codified rules judicially; Canada’s Supreme Court adopted a “principled approach” case by case, replacing fixed rules with flexible standards based on necessity and reliability.

The principled approach applies to hearsay, expert opinion, confessions, and similar-fact evidence. For hearsay, admissibility requires:

• Necessity: The declarant is unavailable (e.g., deceased, infirm).

• Reliability: The statement’s context suggests truthfulness, or tools exist to test its accuracy (e.g., video recording).

The 2006 Khelawoncase exemplifies this: a deceased witness’s statement was excluded due to unreliability (dementia and lack of cross-examination), affirming that principled analysis complements traditional rules.

Challenges include:

1. Coexistence with traditional rules, adding complexity.

2. Subjective reliability assessments, leading to judicial disagreement.

3. Reduced efficiency due to case-specific evaluations.

Yet the approach allows juries to consider more reliable evidence and offers a model for common law reform.

Q&A Session

Question 1: What is the scope of application of the principled approach? Is it limited to the hearsay rule?

The principled approach is most developed in the area of the hearsay rule. In addition to hearsay, the principled approach also applies to areas such as expert opinion evidence, confessions of the accused, and similar-fact evidence. However, it has almost no impact on privilege rules (e.g., solicitor-client privilege), and courts maintain a strict attitude towards privilege rules.

Question 2: Why did the Supreme Court of Canada adopt the principled approach?

I believe it's because Parliament did not adopt a systematic response, so the court felt it could gradually change the law. Furthermore, I think they viewed this as a way to evolve the law incrementally. If they had directly abolished the existing law and proclaimed a new one, they would have been accused of overstepping the powers of the court and judges. A step-by-step pace is more consistent with the common law tradition, where judges have always played a somewhat creative role, but proceed gradually, not in one giant leap.

Question 3: How should the necessity of evidence be understood? Is necessity equivalent to having probative value? Or is it the same as relevance?

This is an excellent question, but the answer is neither. Relevance is a prerequisite for the admissibility of evidence; irrelevant evidence is directly excluded. Necessity is different from probative value; probative value refers to the degree to which the evidence assists in determining facts, whereas necessity relates solely to whether the declarant is available to testify. The three are entirely distinct.

"Why is that person not here?" That is the question of necessity. We do not have a specific list of reasons why hearsay evidence might be necessary. But common reasons include, for example, the person being deceased – that is why we cannot have them testify. Or the person being too young to testify, as in the Khan case. We used to have a rule of spousal incompetency, meaning a spouse could not testify against the other. We no longer have that rule, but we did in the past, and that was another source of necessity then. If an out-of-court statement of the other party was made by the accused's wife, then she could not be called to testify. So, if a person from another country cannot be made to testify, then the statement is necessary. There was a case that touched on this, though it wasn't the central issue of the case; it was just part of the facts. He was accused of murdering a young woman and had a telephone conversation with his wife about it. This was a very important conversation in the case. But she was unavailable to testify. She was originally from Japan. After the incident, she was disgusted and moved back to Japan, so she could not appear as a witness. There is some case law discussing whether a situation where testifying would traumatize a child constitutes necessity? In the KGB case, there were three young men. KGB was a young man accused of manslaughter. The prosecution alleged he killed someone in a fight, and there were three witnesses present. They told the police that KGB did it. But at trial, they said, "No, we know nothing about it." The court held that their recantation made their prior statements necessary. There are no fixed categories. It depends on why we cannot get the information directly from the declarant.

I'm sorry I cannot give you a definition. I know I'm just giving you examples. But that's how the case law defines it. In most cases, the witnesses involved are either deceased or have recanted their testimony, so the necessity is clear.

Question 4: Will Canada enact a uniform evidence code in the future?

I think it's highly unlikely. In the 1970s, scholars and lawyers drafted a Uniform Evidence Act, but it was not passed due to political reasons such as elections. Evidence law is not a hot political topic in Canada; no political party would use it as a campaign platform. Therefore, there will be no systematic legislative reform in the short term, and the Supreme Court will continue to advance reforms gradually through case-by-case decisions.

A more practical question, I think, is that the Supreme Court of Canada has not yet opined on many evidence rules, leaving them with a very traditional structure. Will the Supreme Court of Canada do something about such evidence rules? I believe the Supreme Court of Canada will likely continue to tinker with evidence law in the common law way.

Question 5: How is evidence classified in Canada?

We don't classify evidence in the same way China does. We classify evidence based on how the jury will handle it: Is it hearsay? Are we to believe the truth of this statement? Will they accept the witness's opinion? These are characteristics. Therefore, we classify evidence based on how the fact-finder uses it, not based on whether a document or something might be hearsay. In fact, they often are hearsay. As we saw in the Khan case, a video recording can be hearsay. So, the classification methods in our two countries are different. But regarding your question, I want to touch on another aspect. Probative value is not predetermined; it is always determined based on the specific circumstances because you cannot judge in advance whether a document will become evidence. A document might be full of lies, or it might be an accurate statement – you cannot know in advance. The probative value of evidence is always determined by the trial judge on a case-by-case basis.

Question 6: What is the purpose of the principled approach? It seems to allow more evidence into the courtroom, making convictions easier. What was the court's reason for making this reform?

I will answer your question, but let me first address part of your premise, even if it might not have been intentional. Often, the principled approach might make it easier for evidence to enter the courtroom, but not always. For example, in the area of similar-fact evidence, the principled approach might make it more difficult, becoming stricter and more challenging for the prosecution. Some argue that the principled approach can be used both to exclude hearsay and to admit hearsay. When hearsay evidence is admissible under traditional rules but is genuinely unreliable, it should be excluded. So, the motive is not directly to obtain more convictions; the motive is to provide the jury with more reliable evidence. Usually, these changes benefit the prosecution, but that is because the prosecution bears the burden of proof. Therefore, any rule change that facilitates the admission of evidence will tend to benefit the prosecution, but that is not the direct purpose. The direct purpose should be to enable the jury to receive reliable information. For example, in the area of expert evidence, in the past, experts could say almost anything in court and be believed by the jury. So, the reform in expert evidence was actually aimed at reducing, not expanding, the gateway for evidence entering the courtroom. So, I truly believe the more important goal is to make evidence more reliable, not to get more people convicted.

Question 7: Canada's principled approach is praised by some, but in China, when courts enjoy significant discretionary power, it often faces query from academia. How do you view this issue?

Thank you for your question. I think this is a very serious issue. The principled approach essentially grants a power to exclude prejudicial evidence. This relies heavily on trust in the judge's exercise of discretion. That is absolutely true. It's quite interesting that, except in journals, I rarely see criticism in the field of evidence law about courts having too much power. I think the reason might be that evidence law is very practical, day-to-day work for judges and lawyers. Even if we might distrust them on other major social policy issues, we can trust them on this because it's so practical; it's their daily work. They might not be very knowledgeable about some contentious social policy issues, but perhaps they understand evidence rules best. These are some of my speculative thoughts.

Question 8: What is the relationship between the principled approach and the constitution?

Canada's Constitution Act, 1982, including the Canadian Charter of Rights and Freedoms, provides important context. Particularly, Section 7 states that "Everyone has the right to life, liberty and security of the person and the right not to be deprived thereof except in accordance with the principles of fundamental justice." The Supreme Court has made clear in its jurisprudence that the principle that "probative value must outweigh prejudicial effect" is a principle of fundamental justice at the constitutional level. Statutory reforms must conform to this principle; otherwise, they risk being declared invalid.

Question 9: In judge-alone trials without a jury, can the determination of evidence admissibility be postponed until the end of the trial?

This is a very good question. For expert evidence, some judges may postpone the determination to enhance efficiency. However, for hearsay evidence, judges usually make the determination at the time the evidence is tendered. Otherwise, the parties' arguments at the end of the trial would lack a clear basis, as it would be uncertain which evidence can be relied upon.

Translated by: Guo Zhongqi

Edited by: Zhang Wenyi