Evidence: overview of the principles of relevance and admissibility

By Robert Wilson

This is an extract from Lawbook Company's Nutshell: Evidence  by Robert Wilson (Sydney: LBC, 1999, 1st ed). LBC Nutshells are the essential revision tool: they provide a concise outline of the principles for each of the major subject areas within undergraduate law. Written in clear, straightforward language, the authors clearly explain the principles, and highlight key cases and legislative provisions for each subject. Observed facts This is more a general principle that any specific rule however, it has important ramifications. A witness may only give evidence of facts that the witness has actually observed. When a witness' testimony contains, even in part, any assertion of fact as to something that that witness did not observe, then prima facie that part of the testimony is inadmissible, it usually being excluded by either the hearsay rule or the opinion evidence rule. Relevant evidence This is a general principle that is usually stated in the form that only evidence that is relevant to a fact in issue is admissible. The evidence will be relevant only if it is capable of assisting the inquiry, one way or the other, when determining the existence of an alleged fact. It also has a corollary in that all relevant evidence is admissible in the proceedings unless that evidence is specifically excluded by some other principal or by some discretionary rejection. This general principle and its corollary provide an overall framework namely, that all relevant evidence is admissible unless specifically excluded by a particular exclusionary principle. It also serves the purpose of excluding some factual information concerning the genesis and development of the legal dispute that has no evidential value in relation to the facts in issue. Generally, it is our experience of life, including any technical or scientific knowledge that we may have, that permits us to decide what is relevant and what is not. Evidence may be relevant for any number of reasons and of course it will depend very much upon the circumstances surrounding each fact we are inquiring into. The question of whether evidence is relevant mainly arises when a party attempts to prove a fact in issue by tendering circumstantial evidence and the other side objects to the tender of this evidence on the basis that it is incapable of assisting the inquiry into the existence of the fact in the issue. Hearsay If evidence amounts to hearsay it is excluded. Whether or not evidence is hearsay is a fairly complex issue. For present purposes hearsay may be conceptualised as a statement by a witness that a fact occurred, when the witness did not actually observe the occurrence of that fact, or a statement in any document that a fact occurred, irrespective of who wrote that statement, provided that, in both cases, the purpose of the witness' testimony, or the tender of the document, is to prove that the fact that was asserted therein did in truth occur. Thus, a witness may not say in evidence what someone else told that witness about the occurrence of the fact in issue and a document is not admissible if it contains a statement about the occurrence of that fact in issue. Both will be rejected as hearsay if the purpose of the evidence is to prove the fact asserted therein. The general rationale of this exclusionary rule is to confine the evidence to direct testimony, that is, to evidence by a witness who actually observed the event happening. Note that if the purpose of the witness' testimony is only to prove that that other person simply made that statement, rather than to prove the truth of the fact asserted in that statement, the evidence does not amount to hearsay. Equally, if the purpose of the document is only to prove what another person wrote, and nothing more, the statement in the document is not hearsay because it is not thereby intended to prove the truth of the fact being asserted. In both these instances the evidence does not even amount to hearsay in the first place. Rather, it is classified as "original evidence". Also note though that even if evidence is tendered which is hearsay it may nevertheless be admitted by reason of one of the many qualifications to the exclusionary nature of the hearsay rule. These qualifications are generally referred to simply as exceptions to the hearsay rule. Thus the hearsay rule excludes relevant evidence if it be hearsay in nature unless an exception to the hearsay rule applies. Opinion Evidence which does no more than assert an opinion, for example that a person's conduct was careless, is inadmissible. Basically, this is a question of form as a witness may always narrate the acts of a person which the witness directly observed. The witness however cannot go further and proffer the opinion that those facts amounted to carelessness as to do so is really to draw an inference from observable facts or to reach a conclusion. This rule though is qualified; for example, where expert evidence is called for an expert is entitled to express an opinion. Public interest The common law has long recognised the need in appropriate circumstances to prohibit disclosure of facts where such disclosure would be unduly adverse to the public interest. This prohibition has taken two quite distinct forms: (a) where the disclosure of facts would be injurious to the interests of the State, evidence as to those facts is prohibited. This is referred to as public interest immunity; and (b) where evidence has been obtained illegally or improperly, that evidence may be rejected in the exercise of a discretionary power to do so. Privilege Equally, the common law prohibits the disclosure of facts that fall within one of the recognised privileges (the privilege against self- incrimination, marital privilege and legal professional privilege). The same applies to statements made "without prejudice". Even at common law there are exceptions and qualifications to these propositions. Character Evidence The type of evidence for consideration here is evidence where a witness expresses a personal opinion as to another person's character, states that the witness would or would not believe what that other person said on oath or states what the witness believes that other person's reputation to be amongst those who know him (or her). This type of evidence is to be distinguished from propensity evidence, that is, from evidence where a witness deposes as to specific acts (which are often wrongful or improper acts) done by a witness in the past. Propensity evidence (often referred to as a similar fact evidence) is governed by its own specific rules. All these types of evidence tend to show character, whether good or bad. This area is conceptually very difficult and perhaps the best way to approach it is with the basic idea that evidence which shows character is not admissible unless: (a) it is one of the recognised forms of Character Evidence (see below); or (b) it is one of the exceptions to the propensity rule (discussed in the next sub-heading). The antiquity of the rules relating to Character Evidence have tended to allow them to fall into obscurity in modern times and to give a concise overview of the principles upon this point is difficult. However, as a broad statement it can fairly confidently be said that evidence as to the character of parties and witnesses cannot be lead in evidence except that: (a) evidence of the good character of the accused in criminal proceedings may always be adduced by the accused; (b) evidence of character may adduced to impugn the credibility of any witness in the proceedings, including a party who gives evidence ; and (c) if the character of a party is actually a fact in issue (as in defamation proceedings) this exclusionary rule does not apply. This broad statement of the relevant principles though is no more than a starting point and further elaboration will be necessary. Propensity evidence In addition to the above, there is a very old rule at common law that will exclude any evidence which tends to show that an accused in criminal proceedings has a disposition towards wrongdoing either of a civil or criminal nature. The rationale for this rule is that it is not acceptable to try and prove that the accused committed the crime the subject of the proceedings by proving that he or she committed crimes, or did other wrongful acts, in the past. The best way to approach this rule is to see it as one which excludes any evidence which falls within its parameters. There are several well established exceptions to this exclusionary rule all of which basically come into play when the evidence is relevant for some other reason than that it shows disposition towards wrongdoing. This principle is often referred to as the "similar fact evidence" exclusion rule, which is somewhat of a misnomer. This principle most frequently arises in criminal proceedings where evidence is tendered by the prosecution which shows that the accused has committed a similar, or some other, crime in the past. Note that any evidence which shows disposition will always, at least to some extent, show character as well. Therefore this exclusionary rule and the general rules concerning character evidence need to be compared to see whether they are compatible and, if not, the relationship between them must be analysed. Other aspects of the laws of evidence Apart from the issues as to relevance and admissibility which have been summarily mentioned above the laws of evidence govern many other aspects of the process of persuading a tribunal of fact to find that a particular fact occurred. Issues may arise as to whether a witness is competent and compellable, whether a witness' credibility may be impeached, whether corroboration is required, where the burden of proof lies, what standard of proof the evidence must achieve, whether one party is prevented (estopped) from calling evidence that is otherwise relevant and admissible, whether a witness may refresh memory by reference to a document and the extent to which inferences may properly be drawn from circumstantial evidence, to name but a few. All these issues are within the province of the laws of evidence and they are considered in the text that follows under their traditional headings. Jurisdictional variations The principles of evidence that developed at common law are subject to statutory modification in all Australian jurisdictions, each jurisdiction having its own Evidence Act as well as other statutes which contain certain specific provisions affecting the laws of evidence. NSW and the ACT introduced, in 1995, Evidence Acts that are almost uniform with the Evidence Act 1995 (Commonwealth), the latter Act applying in all Commonwealth Courts. For convenience these several Acts are referred to compendiously as the 1995 Uniform Acts. They have come very close to a codification, however the common law still has significant application both in its own right and in explanation of many of the statutory provisions. The other jurisdictions apply common law principles save to the extent that they are modified by applicable statutory provisions. The variations that are to be found in these jurisdictions are not as extensive as the variations effected by the 1995 Uniform Acts. Despite these statutory provisions a sound knowledge of the common law evidentiary principles is still necessary in order to understand the nature of the modifications that have been effected and to present evidence properly when the statutes are silent. Robert Wilson BA LLM Barrister Wentworth Chambers 1999


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