Law of Evidence common mistakes
Law of Evidence · Understand the traps and how to avoid them.
When asked whether evidence is admissible, the candidate answers only that it is 'relevant' and stops there, never moving on to the exclusionary rule (hearsay, bad character, confession, s.78-style discretion) that actually decides the question.
Candidates treat relevance as a conclusion rather than the first gate, because textbooks introduce relevance first and the phrase 'relevant evidence is admissible' gets memorised as a rule of decision. Under exam pressure the familiar word triggers a stop.
What to do instead
Use a fixed two-stage template for every admissibility question: (1) Is it relevant, and to what fact in issue? (2) Which exclusionary rule or discretion applies, and what is the result? Write the headings 'Relevance' and 'Exclusion' before writing any prose, and never let the answer end at stage one.
The candidate states the burden and standard of proof as a single proposition ('the prosecution must prove the case beyond reasonable doubt') and applies it to every issue, including defence claims such as self-defence, automatism, or exceptions to a hearsay rule.
The general criminal standard is taught first and most vividly, so candidates collapse the legal burden, the evidential burden, and the reverse burdens created by statute or common law into one sentence. They also forget that some burdens are borne by the defence on the balance of probabilities.
What to do instead
For every proof question, produce a three-row table: who bears the legal burden, who bears the evidential burden, and what standard applies to each. Then check for a statutory reverse burden and note whether it is compatible with the presumption of innocence. Answer the specific issue asked, not the general rule.
The candidate treats a child or a person with a mental disorder as automatically incompetent, or assumes a spouse is never compellable, without applying the statutory test of competence and the specific compellability exceptions.
Competence and compellability are taught as a list of categories, and candidates memorise 'children are vulnerable' or 'spouses cannot be forced' as slogans rather than as tests with conditions and exceptions.
What to do instead
Learn competence as a two-part statutory test (understanding the questions and the duty to answer truthfully) that applies to all witnesses regardless of age, and learn compellability as a separate list of named exceptions with their conditions. In the exam, state the test, apply it to the facts given, and only then conclude.
When a witness gives evidence of what someone else said, the candidate labels it hearsay and stops, without asking whether it is admitted for a non-hearsay purpose, whether an exception applies, or whether the maker is available for cross-examination.
The definition of hearsay is learned as 'an out-of-court assertion offered to prove its truth', and candidates apply the label mechanically to any reported speech, missing the purpose for which the evidence is tendered.
What to do instead
For every reported statement, ask three questions in order: What is the statement offered to prove? If not its truth, it is not hearsay at all. If its truth, does a recognised exception apply? If no exception, is it admissible for a different, legitimate purpose? Write the purpose explicitly before the label.
The candidate analyses a confession only for voluntariness and oppression, and never considers the statutory exclusion of unreliable confessions or the discretion to exclude evidence whose effect is unfair, nor the special rules on facts discovered as a result.
Confession law is remembered through the dramatic cases on oppression and inducements, so the reliability limb and the discretion are under-revised. Candidates also forget that evidence derived from an excluded confession may still be admissible.
What to do instead
Build a checklist for every confession: was it made to a person in authority, was it voluntary, was it reliable, should it be excluded as unfair, and what happens to derivative evidence? Address each limb separately and give a conclusion on each, even if briefly.
The candidate argues that improperly obtained evidence is automatically inadmissible because it was obtained unlawfully, or conversely that it is always admissible because there is no rule of automatic exclusion.
Both slogans are half-true and easy to remember. Candidates learn one and apply it absolutely, missing that the decision is a discretionary balancing exercise and that the seriousness of the impropriety is only one factor.
What to do instead
State the governing principle as a discretion, not a rule: unlawfulness is relevant but not decisive. Then apply the factors (nature and gravity of the impropriety, whether it was deliberate or in good faith, the availability of other investigative routes, and the effect on the fairness of the proceedings) to the facts given.
The candidate treats 'bad character' and 'similar fact' as interchangeable labels and fails to identify the specific gateway or category through which the evidence is admitted, or the specific purpose for which it is tendered.
The terminology overlaps in ordinary usage, and candidates revise the topic as a single block of 'previous misconduct evidence' rather than as a set of distinct statutory gateways and common law categories with different tests.
What to do instead
For every character or similar fact question, name the gateway expressly (for example, propensity, a matter in issue between the parties, or correction of a false impression) and state the purpose for which the evidence is admitted. Then assess probative value against prejudicial effect within that gateway.
The candidate offers an opinion on the ultimate issue, or accepts a non-expert's opinion as admissible, without distinguishing expert opinion from lay opinion and without stating the basis on which the expert's opinion is admissible.
The opinion rule is often reduced to 'experts can give opinions', which obscures both the lay opinion exception and the requirement that expert evidence be within a recognised field and based on relevant expertise.
What to do instead
Before admitting any opinion, classify it: lay opinion (permissible where it is a compendious way of describing what the witness perceived) or expert opinion (permissible where the subject is outside ordinary experience and the witness is qualified). State the classification and the reason in one sentence each.
The candidate answers a problem question as a general essay on the law, listing rules without applying them to the named parties and facts, and reaches no conclusion on the specific issue asked.
Time pressure and heavy revision notes encourage rule-dumping. Candidates fear committing to an outcome, so they describe the law and leave the application implicit, which earns no application marks.
What to do instead
Use an issue, rule, application, conclusion structure paragraph by paragraph. Every rule sentence must be followed by a sentence naming the party and the fact it applies to, and every section must end with a stated outcome. If the facts are ambiguous, say which way the answer turns on each reading.
The candidate cites a case name as the whole answer ('this is the principle in X') without stating what the case decided, or cites a case for a proposition it does not establish.
Cases are memorised as labels attached to topics rather than as reasons. Candidates reproduce the name as a substitute for the rule and cannot check whether the proposition matches the facts.
What to do instead
For each key authority, learn a one-line holding in the form 'case name: facts in one clause, rule in one clause'. In the exam, write the rule first and the case second as support. If you cannot state the holding, omit the citation rather than risk a misdescription.