LAWS50037 · Evidence And Proof
Discretionary Exclusions
The discretionary and mandatory exclusions are the final filter of the admissibility ladder. Every other rule (relevance, hearsay, opinion, tendency) is about whether evidence gets in; this chapter is about whether even relevant, exception-satisfying evidence should be kept out because its probative value is outweighed by danger to the trial. The legal question is always the same cost-benefit — probative value vs prejudicial effect — but the standard, who it protects, and whether the court ‘may’ or ‘must’ exclude differ by section: s 135 (general discretion: ‘may’, ‘substantially outweighed’, all proceedings, including the Victorian s 135(d) on demeaning the deceased in homicide), s 136 (limit the use), s 137 (mandatory: ‘must’, ‘outweighed’, prosecution evidence in crime), s 138 (improperly/illegally obtained, weighing the eight s 138(3) factors), and s 90 (the admissions fairness discretion). Probative value is assessed ‘at its highest’ (IMM v The Queen). This is the chapter where strong exam answers separate, because most candidates only flag ss 135/137/138 — getting to the nub of the balance is where the marks are.
What this chapter covers
- 01The cost-benefit: probative value vs prejudicial effect
- 02s 135 — the general discretion (may; substantially outweighed; all proceedings)
- 03s 136 — limiting the use of evidence
- 04s 137 — mandatory exclusion of prosecution evidence in crime (must; outweighed)
- 05The s 135 / s 137 asymmetry — the single most-confused point
- 06s 138 — improperly/illegally obtained evidence and the eight s 138(3) factors
- 07s 90 — the admissions fairness discretion · probative value ‘at its highest’ (IMM)
Worked example: which discretion, and how does the balance resolve?
- +1Pick the section. It is prosecution evidence in a criminal trial, so the operative provision is s 137 (mandatory) — do not default to s 135.
- +1Probative value (IMM). Assess PV with the evidence taken ‘at its highest’; but the poor quality of the footage is a ‘foggy-night’ factor that caps how high the highest point reaches.
- +1Name the unfair prejudice. The specific danger is that the jury will give the suggestive interpretation more weight than its true probative value warrants — misuse, not mere damage to the case.
- +1Apply the s 137 standard. The court must exclude if probative value is outweighed (no ‘substantially’) by the danger of unfair prejudice to the accused.
- +1Resolve at the nub. State how the balance comes out and that it turns on the trial judge’s view of the footage’s true value against the identified prejudice — not a bare assertion that ‘s 137 might apply’.
Key terms
- s 135 (general discretion)
- In all proceedings the court may refuse evidence if its probative value is substantially outweighed by a danger that it might be unfairly prejudicial, misleading or confusing, or cause undue waste of time — and (Victoria, s 135(d)) unnecessarily demean the deceased in a homicide proceeding. Discretionary; any party.
- s 137 (mandatory exclusion)
- In a criminal proceeding the court must refuse to admit prosecution evidence if its probative value is outweighed (no ‘substantially’) by the danger of unfair prejudice to the accused. The operative provision for prosecution evidence in a Victorian criminal trial.
- The s 135 / s 137 asymmetry
- They are not interchangeable. s 135: all proceedings, ‘may’, ‘substantially outweighed’, any party. s 137: criminal only, ‘must’, ‘outweighed’, prosecution evidence and the accused only. Do not default to s 135 for prosecution evidence in crime.
- s 138 (improperly/illegally obtained)
- Evidence obtained improperly or in contravention of an Australian law (or in consequence of) is not admitted unless the desirability of admitting it outweighs the undesirability, weighing the eight factors in s 138(3). A discretionary balance, not an automatic exclusion.
- Unfair prejudice
- Not mere damage to a party’s case — that is the point of probative evidence — but the danger the tribunal will misuse the evidence or give it more weight than it rationally deserves. Naming the specific unfair prejudice (not just ‘it’s prejudicial’) is what earns the marks.
Discretionary Exclusions FAQ
What is the difference between s 135 and s 137?
They differ on four axes. s 135 applies in all proceedings, is discretionary (‘may’), uses the higher ‘substantially outweighed’ standard, and is available to any party. s 137 applies in criminal proceedings only, is mandatory (‘must’), uses the lower ‘outweighed’ standard, and protects the accused against prosecution evidence. In a Victorian criminal prosecution, s 137 is almost always the operative provision for prosecution evidence — do not default to s 135.
How do I assess probative value for the discretions?
With the evidence taken ‘at its highest’ (IMM v The Queen): assume it is accepted, and do not discount for the witness’s reliability or credibility. But a factor may cap how high the ‘highest point’ reaches — the ‘foggy-night’ qualification — so genuinely poor-quality evidence has a low ceiling. That single probative-value figure then drives ss 135, 137 (and ss 97, 98, 101).
What counts as ‘unfair prejudice’?
Not the ordinary damage that any cogent prosecution evidence does to the defence — that is simply probative force. Unfair prejudice is the risk the tribunal will misuse the evidence or give it more weight than it rationally warrants (e.g. emotive reasoning, or treating a suggestive interpretation as stronger than it is). The marks come from naming the specific unfair prejudice and weighing it against the assessed probative value.
Why do strong answers do better on the discretions than elsewhere?
Because most candidates only flag ss 135/137/138 and move on, while the marker’s feedback rewards engaging the cost side in detail. To get to the nub: identify the right section (mind the s 135/s 137 asymmetry), assess probative value per IMM, name the specific unfair prejudice, and state precisely how and why the balance resolves — acknowledging it turns on the trial judge’s view. This is the chapter where the strongest exam answers are made.
Exam move
For each significant chain of your proof, ask whether a discretion bites — and then go past flagging it. Pick the section precisely (the s 135/s 137 asymmetry is the most-confused point: may/must, substantially-outweighed/outweighed, all-proceedings/criminal, any-party/prosecution-v-accused). Assess probative value ‘at its highest’ per IMM, allowing for the ‘foggy-night’ cap. Name the specific unfair prejudice, not a bare ‘it’s prejudicial’. For s 138, walk the eight s 138(3) factors. Then state how and why the balance resolves, acknowledging it turns on the trial judge. This is the chapter where strong answers separate, so practise reaching the nub of the balance, not just the existence of the discretion.
