The Central Gatekeeping Principle of Rules 404–415
Evidence can be logically relevant and still be excluded! These doctrines do not begin with the conclusion that the evidence lacks probative value. In many situations, prior acts or insurance strongly affect ordinary probability.
"Relevant evidence may still be excluded because the law distrusts the inference (propensity) or wishes to promote an important external policy (safety repairs, settlements, medical charity, plea bargains, insurance neutrality)."
Students must always articulate the dual inferential chain: what is the prohibited reasoning versus the legitimate non-propensity or policy-permitted reasoning?
Rule 404(a): The Propensity Prohibition & Exceptions
The Prohibited Chain: Character evidence generally cannot be introduced to prove that a person possesses a character trait and therefore acted in accordance with that trait on the occasion being litigated:
Defendant is violent → violent people commit assaults → Defendant committed this assault.
The Criminal Defendant's Character (Rule 404(a)(2)(A)): A criminal defendant may offer evidence of the defendant's own pertinent trait (e.g., peacefulness in an assault prosecution). The prosecutor may then offer evidence to rebut it. Rule 405 ordinarily limits direct proof to reputation or opinion; on cross-examination, the court may allow inquiry into relevant specific instances.
Alleged Victim's Character (Rule 404(a)(2)(B)): A criminal defendant may offer evidence of a pertinent trait of the alleged victim (e.g., violent character to support self-defense). If admitted, the prosecution may rebut the victim's trait or offer evidence of the defendant's same trait.
Special Homicide First-Aggressor Rule (Rule 404(a)(2)(C)): In a homicide prosecution, the prosecutor may offer evidence of the alleged victim's peacefulness to rebut evidence that the victim was the first aggressor—even if the defense did not first offer character evidence about the victim.
Rule 405: Methods of Proof & Character as an Essential Element
When Character Is an Essential Element (Rule 405(b)): When a person's character or trait is an essential element of a charge, claim, or defense, it may also be proved by relevant specific instances of conduct. The setting is uncommon. Depending on governing substantive law, negligent entrustment may put the entrusted person's competence or fitness directly at issue; prior incidents may also be independently relevant to the entrustor's notice or knowledge.
Circumstantial Character Proof (Rule 405(a)): When evidence of a character trait is admissible for a circumstantial character use, it may be proved on direct examination by reputation testimony or opinion testimony. Rule 405(b) separately permits specific instances when the trait itself is an essential element.
Cross-Examination of Character Witnesses: On cross-examination, the court may allow inquiry into relevant specific instances of conduct. The rule authorizes inquiry; it does not itself authorize extrinsic proof of those acts, and other evidentiary limits still apply.
Rule 404(b): Non-Propensity Uses (MIMIC-POPA) & Rule 403
Evidence of any other crime, wrong, or act is not admissible to prove a person's character in order to show that on a particular occasion the person acted in accordance with the character. But it may be admissible for non-propensity purposes:
- Motive: Earlier dispute provides specific reason for hostility.
- Intent & Knowledge: Prior deliberate use makes accidental conduct improbable.
- Mistake (Absence of) / Lack of Accident: Refutes defense of inadvertence.
- Identity (Modus Operandi): Requires distinctive signature similarity (e.g., robber leaving an origami crane with coded cipher), not generic similarity!
- Common Plan / Scheme: Steps in an overarching unified plot.
- Opportunity / Preparation: Access to restricted keys, uniforms, codes.
Crucial Guardrails: A label such as “motive” is not enough. The proponent should articulate a relevance chain that does not depend on propensity, and the point must matter in the case. The court must also apply Rules 401–403. In a criminal case, Rule 404(b)(3) ordinarily requires reasonable pretrial notice; on a timely request, Rule 105 requires an appropriate limiting instruction.
Rule 406: Habit and Routine Practice vs. General Character
Evidence of a person's habit or an organization's routine practice may be admitted to prove that on a particular occasion the person or organization acted in accordance with the habit or routine practice.
Useful habit indicators (not a rule-text checklist):
1. Specificity: How specific is the recurring situation?
2. Regularity: How invariable and uniform is the response?
3. Regular response: Does the conduct resemble a repeated response to that situation rather than a broad disposition?
4. Quantity: Numerous documented instances.
• Character: “D is a careful person” or “D is a reckless driver” describes a broad disposition and ordinarily may not prove conduct on the occasion.
• Habit: “Each time the pharmacist releases a controlled drug, the pharmacist checks the patient ID against two records” describes a specific, repeated response. Rule 406 says the court may admit habit or routine-practice evidence, whether corroborated or witnessed.
Rules 407–411: The Specialized Policy Exclusions
- Rule 407 (Subsequent Remedial Measures): A later measure that would have made earlier harm less likely cannot prove negligence, culpable conduct, a product defect, or a need for warning or instruction. The court may admit it for another purpose, such as impeachment or—if disputed—ownership, control, or feasibility. “Impeachment” cannot be a pretext for the prohibited inference.
- Rule 408 (Compromise Offers & Negotiations): When offered to prove or disprove the validity or amount of a disputed claim—or to impeach by a prior inconsistent statement or contradiction—the rule excludes offers, acceptances, and conduct or statements during compromise negotiations. It allows other-purpose uses such as bias, negating undue delay, or proving obstruction. A special exception may apply in a criminal case to negotiations about a claim by a public office exercising regulatory, investigative, or enforcement authority.
- Rule 409 (Offers to Pay Medical Expenses): An offer or promise to pay medical, hospital, or similar expenses is inadmissible to prove liability. The rule does not itself exclude an accompanying factual statement, but that statement remains subject to every other applicable evidence rule.
- Rule 410 (Pleas and Plea Discussions): Specified pleas and plea-related statements generally are inadmissible against the defendant. Protected plea-discussion statements must be made with an attorney for the prosecuting authority and satisfy the rule's conditions. The rule contains fairness/completeness and perjury-or-false-statement exceptions.
- Rule 411 (Liability Insurance): Evidence that a person was or was not insured cannot prove negligent or otherwise wrongful conduct. It may be offered for another purpose—such as bias, agency, ownership, or control—subject to Rule 403 and other rules.
Rules 412–415: Sexual-Misconduct Doctrines & Statutory Exceptions
Rule 412 (Sex-Offense Cases: The Victim): In a civil or criminal proceeding involving alleged sexual misconduct, evidence offered to prove a victim's other sexual behavior or sexual predisposition is generally barred.
Criminal Exceptions: Specific acts to prove someone else was source of semen/injury; specific instances with the accused to prove consent; or evidence whose exclusion would violate the Constitution.
Civil Standard: Evidence is admissible only if its probative value substantially outweighs the danger of harm to a victim and unfair prejudice to any party; reputation evidence is admissible only if the victim placed it in controversy. Rule 412(c) ordinarily requires a motion at least 14 days before trial, notice, an in-camera hearing, and a sealed record unless the court orders otherwise.
Rules 413, 414, and 415 (Specific Propensity-Permitting Rules):
In covered criminal or civil cases, evidence that the defendant committed another sexual assault or child molestation may be admitted and considered on any matter to which it is relevant, including propensity. A conviction is not required, but the proponent still must establish the relevant act and satisfy Rules 401–403, authentication requirements, and other applicable rules. The proponent generally must disclose the evidence at least 15 days before trial, unless the court allows later disclosure for good cause.
Master List of Character & Policy Examination Traps
• Do not assume character evidence is always inadmissible (distinguish propensity from character as an essential element under Rule 405(b)).
• Do not allow specific acts on direct examination to prove a character trait under Rule 405(a).
• Do not recite 404(b) non-propensity labels without articulating the exact non-propensity inferential chain.
• Do not confuse generic crime similarity with distinctive signature modus operandi under 404(b) identity.
• Do not equate repeated behavior with Rule 406 habit without a specific situation and sufficiently regular response.
• Do not apply Rule 407 subsequent remedial measures to feasibility unless feasibility is genuinely contested!
• Do not apply Rule 408 to statements made before a claim arose or before validity/amount was disputed.
• Do not exclude a factual admission under Rule 409 merely because it accompanied an offer to pay medical expenses—but still test other rules.
• Do not forget that Rule 404(a)(2)(C) allows the prosecution in a homicide case to prove victim's peacefulness if defendant claims victim was first aggressor.
• Do not apply Rule 404's ordinary propensity bar to covered Rules 413–415 evidence, but still apply the remaining admissibility requirements.
Authority & Scope Note
This study game is keyed to the official Federal Rules of Evidence amended through December 1, 2025. It is an educational issue-spotting aid, not a substitute for the full rule text, advisory committee notes, controlling precedent, or jurisdiction-specific law.
Open the official Federal Rules of Evidence PDF