The rule that is designed to prevent reliance on this impermissible inference and to identify when discreditable conduct evidence is important enough to admit in spite of the risks it presents is generally known as the "similar fact evidence rule." The rule has been given this label because it developed in cases where the Crown was attempting to prove that the accused person had committed similar acts before. The term "similar fact evidence rule" can, however, be misleading. This is because "the rule also extends to criminal or otherwise discreditable acts that bear no similarity to the offence with which the accused is charged."18It applies, and must therefore be satisfied, in every case where the Crown is presenting evidence to establish the guilt of the
accused19that either directly or indirectly reveals the discreditable or stigmatizing character of the accused. The similar fact evidence rule applies whether the discreditable conduct is criminal or not,20and whether the evidence recounts specific acts or relates directly to who the accused is, rather than to what the accused has done.21The rule is triggered by discredit, not similarity.
The "similar fact evidence rule" was stated with clarity in R. v. Handy:
Similar fact evidence is . . . presumptively inadmissible. The onus is on the prosecution to satisfy the trial judge on the balance of probabilities that in the context of the particular case the probative value of the evidence in relation to a particular issue outweighs its potential prejudice and thereby justifies its reception.22Although this concise articulation of the rule does not speak about the prohibited inference, as will be explained, if this rule is applied properly the prohibited inference will be avoided. The Handy decision is important because it sweeps aside years of confusion in Canada.
The classic approach to similar fact evidence, inspired by Makin v. A.G. for New South Wales,23was for courts to determine the admissibility of similar fact evidence by attempting to identify permissible inferences, in order to avoid the impermissible inference. In an era of formalized precedent, it was not long before courts neglected the difficult challenge of trying to articulate the precise inferences the evidence yielded on the particular facts of the case; instead they relied on the example of previous decisions. This caused courts to develop categories for admission
to simplify things. The most familiar categories involved using similar fact evidence to establish "design," to rebut "accident" or "innocent association,"24and to show identity or the actus reus of an offence by demonstrating a "system," or "hallmark," or some "striking similarity." While each of these categories encompasses situations that can, depending on their particular facts, meet the test articulated in Handy, courts often used these categories as a substitute for thought. Instead of analyzing the evidence closely, they simply used labels as the "open-sesame" to admissibility. A spectacular example is R. v. Clermont,25a
rape prosecution, where the trial judge allowed the Crown to prove that Clermont had been convicted of rape before. Even though the sole issue was consent, and the facts were materially different in each case, the judge justified admissibility by noting that the evidence was adduced to establish a "pattern of similarity" and "to rebut the defence of innocent association or a defence of mistake." He went on to state that the "similarities" were such that the acts in both cases were committed by the same person and that the intention was the same in both cases. Fittingly, the Supreme Court of Canada ordered a new trial.
The similar fact evidence rule was...