Propensity evidence: relevance and probative value

The topics du jour in BBH v R [2012] HCA 9 (28 March 2012) were the requirements of relevance and probative value in relation to the admissibility of propensity evidence.

Everyone agrees that the first requirement for evidence to be admissible is relevance. The evidence must have a tendency to prove a matter in issue in the case. This does not mean it must be looked at in isolation, but assessment of its tendency to prove a matter in issue, its relevance, is made in the context of the other evidence in the case.

All well and good. But judges can differ over whether evidence is relevant. In BBH French CJ, Gummow and Hayne JJ held the contested evidence was not relevant. Their narrow view of it is in contrast to that taken by the other members of the court. French CJ was particularly concerned to avoid circular reasoning [58]: it would be wrong to use other evidence of the offence charged to interpret the tendency of the contested evidence. French CJ described the contested evidence as a "snapshot" of an incident that may or may not have been of the kind that would have made it evidence of similar facts.

But Heydon J [102] rejected the snapshot approach and looked more carefully at the context of the contested evidence, and concluded that it was capable of having the required similarity. So did Crennan and Kiefel JJ jointly [152], [159]. Bell J also noted circumstances in relation to the contested evidence that supported similarity [198].

Once relevance is established, propensity evidence must pass another hurdle. It must reach a required level of probative value. The applicable standard in this case was laid down in Pfennig v R [1995] HCA 7, (1995) 182 CLR 461. This standard is by no means accepted widely, as Crennan and Kiefel JJ note at [134]. In any event, and broadly speaking, it involves pretending that all the contested evidence is accepted at its highest from the prosecution point of view and also pretending that there remains a reasonable doubt about guilt on the other evidence for the prosecution. The test then is, is the contested evidence capable of removing a reasonable doubt about the defendant's guilt? If so, it is admissible as propensity evidence, otherwise not.

French CJ said that even if the contested evidence was relevant so that Pfennig had to be applied, the result would be that it was inadmissible [59], although he did not elaborate. Hayne J, with Gummow J agreeing, came to the same conclusion [81]. There remained a rational explanation consistent with innocence. This seems to mean that even considered with all the other prosecution evidence the contested evidence had so little probative value that it would leave a reasonable doubt about the defendant's guilt.

The other judges concluded that under Pfennig the contested evidence was admissible. It was not circular to look at the contested evidence in the light cast by the other prosecution evidence. Crennan and Kiefel JJ at [159] with Bell J agreeing at [199] stressed the independence of the witnesses to the two events (that is, the witness giving the propensity evidence and the complainant giving evidence of various offences), the absence of collusion, and the unlikelihood of the coincidence of both witnesses giving evidence of similar incidents. The difference from circularity in the relevance assessment is that here, when we get to the Pfennig stage, similarity has been established. Probative value reflects how the contested evidence bears upon the evidence supporting the present allegations.

The correctness of the Pfennig test was not in issue in this appeal: Crennan and Kiefel JJ at [134]. Nor was the judge's direction to the jury that the propensity evidence could only be taken into account if it was proved beyond reasonable doubt. This, as Crennan and Kiefel JJ said [165]-[168], was a consequence of the chain of reasoning analysis in Shepherd v R [1990] HCA 56, (1990) 170 CLR 573. It is not a universal requirement that propensity evidence be proved beyond reasonable doubt; instead it can be treated, once admissible, as just another sort of circumstantial evidence and given some probative value even if doubts about its reliability may persist, as long as it is more probably true than not true. See for example R v Holtz [2003] 1 NZLR 667, (2002) 20 CRNZ 14 (CA). Instead of Pfennig, in New Zealand we use the statutory requirement that the probative value of the propensity evidence outweighs its unfairly prejudicial effect, with specific criteria to be considered: Evidence Act 2006, s 43. These include the extent of the similarity, the number of people making the accusations, whether admission of the evidence would unfairly dispose the fact-finder against the defendant, and whether the fact-finder would give the evidence disproportionate weight.