Relevance 

Before any other question about a piece of evidence can be asked, one question must be answered first: is it relevant? Relevance is the threshold criterion for admissibility in every Australian jurisdiction. It is a low bar, but it is not a formality — evidence that fails it goes no further, and evidence that clears it is not thereby admitted, only eligible to be considered for admission.

The test for relevance

Evidence is relevant if it could rationally affect, directly or indirectly, the assessment of the probability of the existence of a fact in issue in the proceeding, the test stated in s 55 of the Evidence Act 1995 (Cth) and its uniform counterparts² and applied in Smith v The Queen (2001) 206 CLR 650.¹ The test does not ask whether the evidence is compelling, persuasive, or likely to change the outcome — only whether it is capable of rationally bearing on a fact that matters to the case. A single piece of evidence, weak on its own, is still relevant if a rational fact-finder could regard it as making a fact in issue somewhat more or less probable than it would be without it.

Direct relevance exists where the evidence itself is or describes the fact in issue — for example, an eyewitness account of the act alleged. Indirect (or circumstantial) relevance exists where the evidence bears on some other fact, which in turn bears on the fact in issue — for example, evidence of opportunity, motive, or conduct after the event. Indirect relevance is common and legitimate; it simply requires an extra logical step, and that step must itself be rational rather than speculative.

Facts in issue are determined by the pleadings in a civil matter or the charge and any defences raised in a criminal matter. Evidence that bears only on a matter neither party has put in issue is not relevant, however interesting it might be. Relevance is also assessed evidence by evidence, and often only in the context of the case as a whole — an item that seems trivial in isolation may be relevant because of how it connects with other evidence already before the court.

Necessary, not sufficient

Clearing the relevance threshold does the least amount of work an item of evidence can do. It does not mean the evidence will be admitted. Relevant evidence remains liable to exclusion under the rules governing hearsay, opinion, tendency and coincidence reasoning, and privilege, and can be excluded, discretionarily or as of right, where its probative value is outweighed by the risk of unfair prejudice, confusion, or waste of time. Those rules are the subject of their own articles in this module; the point to hold onto here is the sequence — relevance is asked first, and everything else is asked only once relevance is established.

Conversely, evidence that is irrelevant cannot be rescued by any other rule. No exception to the hearsay rule, no expertise on the part of a witness, and no lack of prejudice will make irrelevant evidence admissible. Irrelevance is a complete and final bar.

The jurisdictional split students must hold in mind

Australia does not have a single, uniform national law of evidence. A common statutory template — generally called the uniform evidence law — originated in the Evidence Act 1995 (Cth) and the Evidence Act 1995 (NSW), and has since been adopted, with local variations, by the Commonwealth, New South Wales, Victoria, Tasmania, the Australian Capital Territory and the Northern Territory. Queensland, South Australia and Western Australia have not adopted the uniform evidence law. Those three jurisdictions retain their own evidence law, built primarily on the common law and supplemented by their own, distinct Evidence Acts, which differ in structure and in the content of specific rules from the uniform scheme.

This split matters well beyond terminology. The precise wording of the relevance test, the architecture of the exclusionary rules, and the availability of particular exceptions can all differ depending on whether a matter is being conducted in a uniform evidence law jurisdiction or in Queensland, South Australia or Western Australia. Every article in this module states general principles that hold across Australian evidence law at a conceptual level, but a student answering a problem question must always identify which jurisdiction the facts are set in and check whether the uniform scheme or a non-uniform state's own law governs before asserting the detail of any specific rule.

Applying this in a problem question

1. Identify the fact in issue that the evidence is said to bear on, drawing it from the pleadings or the charge.
2. Ask whether the evidence could rationally affect the probability of that fact — directly, or indirectly through a further rational step.
3. If it fails that test, stop: the evidence is inadmissible and no other rule can save it.
4. If it passes, do not conclude the evidence is admissible — flag that the exclusionary rules and discretionary exclusion must still be considered.
5. Identify the jurisdiction the problem is set in, and note whether it is a uniform evidence law jurisdiction or one of Queensland, South Australia or Western Australia, before relying on the detail of any specific admissibility rule.