11.1 Part 3.6 of the uniform Evidence Acts provides rules for the admissibility and use of evidence of character, reputation, prior conduct or events where the evidence is relevant because it tends to prove a person had a tendency to act or think in a particular way, did a particular act or had a particular state of mind. At common law, such evidence is commonly referred to as ‘propensity’ and ‘similar fact’ evidence.
11.2 An example of the use of such evidence is in the case of R v Straffen. To identify Straffen as having killed a young girl, evidence was admitted that:
Straffen was in the vicinity at the time of the murder;
he had escaped for two hours from a nearby prison where he was being detained; and
the detention was for killing two young girls in precisely the same circumstances as the killing in question.
11.3 The fact that Straffen had killed the other two young girls in the circumstances alleged was not disputed. The evidence was admitted because it showed that Straffen had a tendency to kill in a particular manner and his presence in the vicinity of the murder and the similarities with the killing in question identified him as the killer.
11.4 The relevance and admissibility of the evidence can also be justified using coincidence reasoning. The situation was one where the evidence showed that three young girls had been killed in similar circumstances and it was improbable that the killings would have been the acts of different people. It was established that Straffen had killed the two other young girls and therefore it was highly probable, he being in the vicinity of the murder, that he had killed the third.
11.5 Reference is made in Chapter 3 to the dangers of this sort of evidence, particularly when it concerns evidence of other discreditable conduct. It poses problems for the fact-finding process because the probative value of such evidence tends to be overestimated and the evidence can be highly prejudicial. It also poses risks of unfairness to parties against whom it is led because, without sufficient notice of the evidence, a party may be taken by surprise and be unprepared to meet the evidence. When led against an accused person, its prejudicial effect significantly increases the risk of wrongful conviction. Admitting evidence of other conduct also raises collateral issues that can significantly increase the time and cost of both civil and criminal litigation.
11.6 At common law, when such evidence is adduced by the prosecution in criminal cases to prove tendency or coincidence, it must satisfy the extremely stringent ‘no rational explanation’ test. Under the uniform Evidence Acts, evidence may not be admitted for tendency or coincidence purposes unless it has ‘significant probative value’ and reasonable notice of intention to adduce it has been given to the other parties to the proceedings. Where such evidence is adduced by the prosecution against an accused to prove a tendency or coincidence, it must satisfy the further requirement that the probative value of the evidence must substantially outweigh any prejudicial effect it may have before it can be used to prove a tendency or coincidence.
11.7 In DP 69, the Commissions considered a number of issues that had been raised concerning the operation of each of the relevant substantive sections (ss 97, 98 and 101) and the notice requirement (s 99). Consideration was also given to the question whether, for criminal trials, ss 97–101 should be replaced by a provision which relies upon ‘the interests of justice’ as the test for admissibility—for example, s 398A of the Crimes Act 1958 (Vic). Some new issues were raised in the course of consultations on the Discussion Paper. The major issue that emerged from consultations was whether s 101 should be amended to apply to all evidence of disreputable conduct tendered against an accused person.
R v Straffen  2 QB 911.
Perry v The Queen (1982) 150 CLR 580. One barrister argues that once such evidence is admitted the case is almost decided: G Brady, Consultation, Sydney, 26 August 2005.
Hoch v The Queen (1988) 165 CLR 292; Pfennig v The Queen (1995) 182 CLR 461. Note that the High Court granted special leave on 23 June 2005 in Phillips v The Queen  HCA Trans 455, a case involving the application of Pfennig v The Queen.
Uniform Evidence Acts ss 97–99.
 Ibid s 101.
 Determining whether evidence is tendency evidence for the purposes of s 97; whether s 98 is too narrow in its operation and whether the events to be considered under s 98 include the event the subject of the proceeding; the operation of ss 97 and 98 in civil proceedings and the redrafting of those sections to simplify their language; and the application of Hoch and Pfennig to s 101.
 Whether s 97 strikes the right balance in controlling the admissibility of tendency evidence and the use of ‘significant’ rather than ‘substantial’ in describing the level of probative value required.
Australian Law Reform Commission, New South Wales Law Reform Commission and Victorian Law Reform Commission, Review of the Uniform Evidence Acts, ALRC DP 69, NSWLRC DP 47, VLRC DP (2005), Q 10–1.