Probative value is the product of a number of factors. Although the similar fact evidence rule does not require judges to follow any particular step-by-step approach, a measure of the probative value of the similar fact evidence can be gained by examining
1) the strength of the evidence that the similar acts actually occurred;
2) (a) the connection between the accused and the similar act event, and (b) "the extent to which the proposed evidence supports the inferences sought to be made"38in relation to a specific issue in the case (a.k.a. the "connectedness" between the similar fact evidence and the "questions in issue");39and
3) the extent to which the matters it tends to prove are live issues in the proceedings [the materiality of the evidence].40
"Where admissibility is bound up with, and dependent upon, probative value, the credibility of the similar fact evidence is a factor that the trial judge, exercising his or her gatekeeping function, is . . . entitled to take into consideration."41In other words, the more believable it is that the similar fact event occurred, the more probative value the evidence has. Occasionally, the similar act will have resulted in a conviction, in which case the incident has already been proved beyond a reason-
able doubt.42In other cases it may emerge from circumstantial evidence alone, as in Makin v. A.G. for New South Wales where the actus reus of murder of a particular baby could be inferred from the fact that the Makins had buried twelve babies in the backyards of homes they had lived in over the course of several years.43Where the similar fact evidence depends on the credibility of a witness, a judge should consider whether the testimony is "reasonably capable of belief" before admitting the evidence.44Even then, the more problematic the proof is, the less probative it will be and the less likely admissibility will occur. In R. v. Handy the probative value of the evidence was diminished by serious questions about the credibility of the similar act witness, including material inconsistencies in her account,45and her financial and personal motives to mislead.46
Where the accused has been prosecuted for and acquitted of a prior act of misconduct, it will ordinarily be impermissible to use that prior act as similar fact evidence.47This is because an acquittal is a finding that the accused was innocent of the prior act,48and because the rule of "issue estoppel" bars "the Crown from re-litigating an issue that has been determined in the accused’s favour in a prior criminal proceeding, whether on the basis of a positive finding or reasonable doubt."49There are exceptions to this rule.
The first is known as the Ollis exception, after the illustrative decision.50Ollis was acquitted of false pretences for cashing a cheque when there was no money in his account. He claimed when tried subsequently for passing another dishonoured cheque that he thought there was money in the account at the time. Yet this second event occurred after the first criminal complaint had been made against Ollis making it most unlikely that Ollis would honestly believe there was money in the account. Since the Crown in Ollis was not challenging the earlier acquittal when proving the earlier charge, the Supreme Court of Canada endorsed the Ollis exception in R. v. Mahalingan, holding that the Crown can "lead evidence underlying a previous acquittal to establish the accused’s state of mind in relation to a subsequent charge."51The better view is the broader one that if the fact of the prior charge is relevant - whether to the state of mind or any other live issue in the case - the Crown can lead evidence about it even where there has been an acquittal.
The second exception is the Arp anomaly. This anomaly applies to multi-count indictments - cases where the accused is tried at the same time for more than one act of alleged misconduct. Where this happens and the similar fact evidence rule is satisfied, the Crown can rely on evidence about one charge as similar fact evidence helping to prove another charge.52This is so even though the accused may ultimately be acquitted on one or more of those charges. In other words, a trier of fact will not err in using an allegation as similar fact evidence even where the accused will be acquitted of that allegation at the end of the case. This Arp anomaly is a pragmatic exception. Were it not recognized, it would be perilous to jointly try charges that the Crown wishes to use as similar fact evidence. Judges are expected to reduce the risk that the principles of issue estoppel will be compromised by directing jurors that they should not use counts that they have already decided to acquit on, as similar fact evidence on the remaining charges.53
Where evidence depends for its probative value on the unlikelihood that two or more persons would be making similar false allegations, collaboration or "collusion" between those persons undermines entirely the probative value of the evidence.54"Collusion can arise both from
a deliberate agreement to concoct evidence as well as from communication among witnesses that can have the effect, whether consciously or unconsciously, of colouring and tailoring their description of the impugned events."55Where there is an air of reality to the prospect of collusion "it is not incumbent on the defence to prove collusion."56
"[T]he Crown is required to satisfy the judge on the balance of probabilities that the evidence is not tainted with collusion," failing which the similar fact evidence will not be admitted.57For there to be an air of reality to the prospect of collusion there must be more than proof of opportunity because "[t]he issue is concoction or collaboration, not contact."58Each case will be highly fact dependent. In R. v. Shearing the fact that there were communications between some of the thirteen complainants and that civil proceedings had been commenced by two sisters did not furnish an air of reality that was "sufficiently persuasive to trigger the trial judge’s gatekeeper function."59 By contrast, in R. v. B.(C.)60the Ontario Court of Appeal found an air of reality where the complainants, who were the daughter and granddaughter of the accused, had discussed their allegations and filed a joint lawsuit after the accused punished them financially by firing the daughter and ceasing payments for the granddaughter’s education expenses.
The extent to which the similar fact evidence supports the desired inferences has two components: (1) "connection to the accused" (Is the prior conduct linked to the accused?) and (2) "‘connectedness’ to a properly defined issue" (How informative is the similar fact evidence?).
The relevance of similar fact evidence is predicated on the proposition that the accused did the discreditable acts sought to be proved. If there is insufficient evidence rationally to connect the accused to the simi-
lar fact event, it can yield no logical inferences. In R. v. Sweitzer,61for example, the Crown sought to use eleven allegations of sexual assault committed with the same modus operandi, as mutual similar fact evidence proving that Sweitzer was the perpetrator of each of the assaults. The problem was that none of these incidents could logically prove Sweitzer’s identity because there was no evidence linking him to any of these allegations. There were however, three other allegations that Sweitzer could be linked to. Since the modus operandi was similar, these allegations could be used as similar fact evidence to infer that Sweitzer committed all fourteen similar attacks. Connectedness to the accused of the similar fact episode is a necessary condition to admissibility.
This does not mean that the trial judge has to go so far as to decide that the accused is probably the perpetrator of the similar act. Since the ultimate decision whether to use the similar fact evidence is for the trier of fact, at the admission stage the judge need merely be satisfied that there is some evidence upon which a reasonable trier of fact can make a proper finding that the accused committed that similar act. It will be enough if the evidence linking the accused to the similar act establishes more than a "mere possibility" that he committed it.62Nor does the linking evidence need to be entirely independent of the similar fact evidence. In R. v. MacCormack the similar fact evidence included surveillance tapes showing mannerisms and physical characteristics that helped link the accused to the similar fact events. It would have been "unduly antiseptic" to disregard this and insist that only independent evidence can establish the requisite link.63
Even if a similar fact event did happen and the accused can be linked to the event, the probative value of proving that event will depend on the extent to which, as a matter of human...