Evidence · Lesson 01
Relevance & Rule 403
這一課問的是：證據是否依 Rule 401 相關？且其證據價值能否通過 Rule 403 衡平？
ActorActObjectStandardConsequence
Visual Scene · the picture in your head
Issue. Is the evidence relevant under Rule 401 — and does its probative value survive Rule 403 balancing?
這一課問的是：證據是否依 Rule 401 相關？且其證據價值能否通過 Rule 403 衡平？
Core Terminology · 7 must-know
Tap a card to flip and reveal the meaning.
relevance (Rule 401)
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Evidence having any tendency to make a fact more or less probable.
相關性。
Rule 402
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Relevant evidence is admissible unless rule otherwise excludes.
Rule 402 默認可採。
Rule 403
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Court may exclude if probative value substantially outweighed by danger of unfair prejudice, etc.
Rule 403 衡平。
unfair prejudice
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Tendency to suggest decision on improper emotional basis.
不公平偏見。
logical relevance
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Any tendency to prove a material fact.
邏輯相關。
conditional relevance
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Rule 104(b): admissibility conditioned on fact's existence.
條件相關。
limited admissibility
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Rule 105: admit for one purpose with limiting instruction.
有限可採性。
Issue · what this lesson is really about
Is the evidence relevant under Rule 401 — and does its probative value survive Rule 403 balancing?
這一課問的是：證據是否依 Rule 401 相關？且其證據價值能否通過 Rule 403 衡平？
Trigger words & phrases that should flag this issue:
relevantprobativeprejudicialmaterialof consequenceunfair
Expression Bank · how lawyers actually say it
Six function → sentence patterns. Use these in essay applications.
| Function | English sentence | 中文 |
|---|---|---|
| Apply Rule 401 | Evidence is relevant if it has any tendency to make a fact of consequence more or less probable. | 相關 = 有任何傾向影響重大事實之可能。 |
| Apply Rule 403 | Court excludes if probative value substantially outweighed by unfair prejudice. | 若證據價值被不公平偏見實質超過 → 排除。 |
| Apply 104(b) | Conditional relevance: jury may consider evidence only if it finds conditioning fact. | 條件相關：陪審員須先認定條件事實。 |
| Apply 105 | Court must give limiting instruction on request when evidence admissible only for limited purpose. | 若僅有限可採，應請求發出限制指示。 |
Rule Sentence · the workhorse
Relevant evidence — that which has any tendency to make a fact of consequence more or less probable — is admissible under Rule 402, but may be excluded under Rule 403 if its probative value is substantially outweighed by unfair prejudice, confusion, waste of time, or cumulative effect.
Sentence Anatomy · 5 roles, 5 colors
Every rule sentence breaks into five visual roles.
Actor 行為人proponent of evidence證據提出人
Act 行為offering evidence提出證據
Object 對象evidence證據
Standard 法律標準Rule 401 + Rule 403Rule 401 + Rule 403
Consequence 後果admitted or excluded採用或排除
Casebook Snapshot · a real American case
Old Chief v. United States
Holding. Where a defendant offers to stipulate to a prior felony conviction in a felon-in-possession prosecution, the prosecution's introduction of evidence of the nature of the prior conviction (here, prior assault) over the stipulation may unfairly prejudice the defendant under Rule 403; the stipulation provides the same probative value with much less prejudicial impact.
Why it matters. Old Chief shows Rule 403's teeth: even logically relevant evidence may be excluded when an equally effective, less prejudicial alternative exists.
Old Chief：等效但較少偏見之證據存在時，Rule 403 可排除。
Common Mistakes · what trips students
✗ Rule 403 balance 必須完美平衡。
✓ Rule 403 excludes only if unfair prejudice SUBSTANTIALLY outweighs.
實質超過方排除。
✗ 「prejudicial」即可排除。
✓ Must be UNFAIR prejudice — all evidence is somewhat prejudicial.
須為不公平之偏見。
✗ relevance 須有「決定性」價值。
✓ Any tendency suffices.
任何傾向即可。
Mini IRAC · build the Application
Issue. Should the trial court admit graphic crime-scene photos of murder victims when D has stipulated to cause of death?
Rule. Relevant evidence may be excluded under Rule 403 if its probative value is substantially outweighed by the danger of unfair prejudice.
Application (model). D has stipulated to cause of death; the prosecution seeks to admit highly graphic crime-scene photos. Because Rule 403 excludes relevant evidence when its probative value is substantially outweighed by unfair prejudice, the fact that the stipulation already established cause of death and the photos add substantial inflammatory content with little additional probative value means the balance tips toward exclusion.
Pick the right element for each blank:
g1.
g2.
g3.
Conclusion. Therefore, the photos should be excluded under Rule 403 (subject to court's discretion).
MBE Check · multiple choice
In a fraud trial, P offers evidence that D paid for an expensive yacht the day after the alleged fraud. D objects on relevance. What result?
Mini Essay · write the Application paragraph
Facts. P sues D for negligent driving. P seeks to introduce evidence that D had been drinking that day, even though there is no direct evidence D was impaired. D objects under Rules 401 and 403.
Call. How should the court rule?
Practice Drill · tap to build the rule
Drop the chips here in correct order:
Tap chips to add → tap chips in the target to remove: