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General Principles

Evidence linking the accused to other discreditable acts or conduct is presumptively inadmissible. This is due to the general exclusionary rule against the reception of evidence of general propensity, disposition or bad character.


The onus is on the Crown to satisfy the trial judge on a balance of probabilities that the probative value of the evidence in relation to a particular issue sufficiently outweighs its potential prejudice. 

The Test

(a)     Probative value

The probative value of the evidence is based on the improbability of coincidence between the similar acts and the acts at issue in the proceeding. The court must consider the degree of its relevance to the facts in issue and the strength of the inferences that can be drawn from it. Inferences sought to be drawn must accord with common sense, intuitive notions of probability and the unlikelihood of coincidence.”


The threshold for probative value is very high. The connection must be so strong that “it would be an affront to common sense to suggest that the similarities were due to coincidence.” However, the probative value of the evidence need not be so high that it is virtually conclusive of guilt.


The probative value analysis includes four inquiries:


1.    First, the evidence must relate to a specific issue, so that it is plainly not adduced merely to show that the defendant is of bad character. The court must identify the issue in question and ask how the similar acts tend to prove that issue. Where the issue is actus reus rather than identification, the degree of similarity required is not necessarily higher or lower, but rather the issue is different.


2.    Second, the court must determine whether the similar fact evidence is tainted by collusion, which undermines the improbability of coincidence: [see R v Clause, 2017 ONCA 859 at paras 81-95 for a full review of the factor of collusion in a jury trial]

3.    The proximity in time between past act and current offence. [A long passage of time between the similar acts may serve to defeat an similar fact evidence application: R v PMC, 2016 ONCA 829 at paras 23-26]:

  • the extent to which the other acts are similar in detail to the charged conduct;

  • the number of occurrences of the similar acts:

  • the circumstances surrounding or relating to the similar acts: 

  • any distinctive features unifying the incidents

  • any intervening events that might undermine the probative value, such as evidence of supervening physical incapacity; and

  • any other factor that would tend to support or rebut the underlying unity of the similar acts.

4.     The court must consider the strength of the evidence that the similar acts occurred. For example:

  • have the allegations been admitted in prior proceedings?

  • are the allegations the subject matter of outstanding charges?

  • by what method of proof are the acts to be proved?

  • can the trier of fact fairly assess the evidence in the context of the trial without undue distraction?

  • will the defence be able to fairly respond to the allegations in the context of the prosecution?

(b) Prejudicial Effect


Prejudice takes two forms:

  1. moral prejudice, which may cause the jury to convict the accused on the basis that he is a bad person who deserves to be punished; or

  2. Reasoning prejudice, which diverts the jury from its task and risks the jury giving the evidence more weight than it deserves.

Finally, the court must assess whether the probative value of the similar fact evidence outweighs its prejudicial effect. 

Standard of Review

Absent an error in principle, substantial deference should be given to the trial judge’s balancing of probative value versus prejudicial effect. This deference recognizes that the trial judge is best equipped to assess the impact of the evidence on the jury, in the context of the issues and evidence at trial. 

See R v Bent, 2017 ONCA 722 at paras 32-48, see also para 60

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