The Seven Gatekeeping Questions of Witness Law
Evidence reaches the factfinder through people. Rather than treating “witness testimony” as a single category, disciplined gatekeeping proceeds through six questions:
1. May this person testify? (Competency, Oath, Interpreters)
2. What may the witness testify about? (Rule 602 Personal Knowledge)
3. In what form may the testimony be given? (Rule 611 Mode/Order, Leading)
4. May the witness express an opinion? (Rule 701 Lay vs. Rule 702 Expert)
5. May credibility be attacked? (Impeachment: Bias, 608, 609, Contradiction, Sensory)
6. If attacked, how may credibility be repaired? (Responsive Rehabilitation)
7. Must the witness be excluded or denied access to testimony? (Rule 615)
Rule 601 Competency & Rule 602 Personal Knowledge
Broad Presumption of Competency (Rule 601): Every person is competent unless the Evidence Rules provide otherwise. Age, memory, perception, or communication limitations ordinarily present credibility and weight questions rather than automatic disqualification. In a civil case, however, state law governs competency for a claim or defense as to which state law supplies the rule of decision.
Rule 602 Personal Knowledge: Evidence must support a finding that the witness has personal knowledge; the witness's own testimony may supply that foundation. Confidence alone is not foundation. Rule 602 does not apply to expert testimony governed by Rule 703. Compare:
• “I saw the light turn red.” (Admissible, personal perception).
• “My friend told me the light was red.” (Inadmissible for red light; hearsay and lacks personal knowledge).
Rule Against Speculation: A witness cannot testify about another person’s unobserved secret intent or thought (e.g., “He wanted to kill him” is improper speculation; but testifying that “He raised the knife, shouted 'I'll kill you,' and ran” is permissible perceived conduct).
Rule 603 Oath/Affirmation & Rule 604 Interpreters: An oath or affirmation must impress the duty to testify truthfully. No religious formula required. Interpreters must be qualified and sworn to accurate translation.
Rule 611 Mode & Order • Refreshing vs. Recorded Recollection
Direct Examination: Leading questions should not be used except as necessary to develop the witness's testimony. The rule ordinarily allows them when a party calls a hostile witness, an adverse party, or a witness identified with an adverse party. Courts may also permit focused leading questions for preliminary matters or communication needs under Rule 611(a) and (c).
Cross-Examination: Leading questions are ordinarily permitted. Scope is restricted to matters raised on direct examination and matters affecting credibility, plus judicial discretion.
The Critical Memory Distinction:
• Refreshing Recollection (Rule 612): Memory fails → counsel uses a writing or other stimulus → witness reviews it → witness testifies from present recollection if memory returns. Rule 612 gives the adverse party rights to production, inspection, cross-examination, and introduction of related portions. The proponent does not obtain admission merely because the item refreshed memory, although another evidence rule may independently permit it.
• Recorded Recollection (Rule 803(5)): Witness reviews writing and still cannot remember → record was made/adopted when fresh and accurately reflected knowledge → record is read into evidence (not received as physical exhibit unless offered by adverse party).
Rule 701 Lay Opinions vs. Rule 702 Expert Testimony
Rule 701 Lay Opinions: Permissible when (1) rationally based on witness's perception, (2) helpful to clear understanding or determining a fact, and (3) NOT based on scientific, technical, or specialized knowledge. Examples: estimated speed, apparent intoxication, emotional demeanor, approximate distance, voice identification, or property owner valuation.
Rule 702 Expert Testimony:
1. Qualified: Through knowledge, skill, experience, training, or education (an experienced mechanic can qualify on engine failure without an academic degree!). Expertise must match the specific issue.
2. Helpfulness: Specialized knowledge assists the trier of fact.
3. Sufficient facts or data.
4. Reliable principles and methods. Daubert identifies flexible considerations such as testability, peer review, error rate, standards, and general acceptance; they are not a rigid checklist for every field.
5. Reliable application: The opinion reflects a reliable application of those principles and methods to the facts. The proponent must demonstrate Rule 702's admissibility requirements to the court as more likely than not.
Fit: Reliable scientific method must fit the actual dispute in the case.
Rule 703 Bases: An expert may rely on facts or data personally observed or made known to the expert. If experts in the field would reasonably rely on that kind of information, the basis need not itself be admissible. But the proponent may disclose otherwise inadmissible basis material to the jury only when its value in helping the jury evaluate the opinion substantially outweighs its prejudicial effect.
Rule 704 Ultimate Issue: An opinion is not objectionable merely because it embraces an ultimate issue. Courts nevertheless exclude impermissible legal conclusions under Rules 701–703 and related doctrine. In a criminal case, Rule 704(b) bars an expert from stating whether the defendant did or did not have a mental state or condition constituting an element of the charged crime or a defense.
Impeachment Architecture (Rules 607, 608, 609, 613)
- Bias & Interest: A reason to favor or oppose a party, such as financial interest or a cooperation agreement. Rule 608(b)'s character-specific extrinsic-evidence bar does not control bias proof; extrinsic proof may be admitted subject to relevance, Rule 403, and applicable procedural foundations.
- Prior Inconsistent Statements (Rules 613 & 801(d)(1)(A)): A prior inconsistency may impeach. For substantive treatment under Rule 801(d)(1)(A), the declarant must testify and be subject to cross-examination, and the inconsistent statement must have been made under penalty of perjury at a trial, hearing, other proceeding, or deposition. Rule 613(b), amended in 2024, ordinarily requires the witness's opportunity to explain or deny before extrinsic proof is admitted, unless the court orders otherwise.
- Rule 608(a) Reputation/Opinion: Truthful or untruthful character. Truthful character evidence is allowed ONLY after truthfulness has been attacked.
- Rule 608(b) Specific Acts: On cross-examination, the court may permit inquiry into specific acts probative of a witness's character for truthfulness or untruthfulness. Extrinsic evidence is barred when offered to prove that conduct for this character purpose; the rule does not create a universal bar when the evidence is independently admissible for bias or another proper purpose.
- Rule 609 Criminal Convictions:
• Dishonest act or false statement: The conviction must be admitted under Rule 609(a)(2) only when the court can readily determine that establishing the crime's elements required proving—or the witness's admitting—a dishonest act or false statement.
• Other Felonies (Witness): Admitted subject to ordinary Rule 403 (exclude if prejudice substantially outweighs probative value).
• Other Felonies (Criminal Defendant Witness): Admitted ONLY if probative value outweighs prejudicial effect (reverse-403 standard favoring exclusion).
• More than 10 years: Measure from the later of conviction or release from confinement. The conviction is admissible only when its probative value, supported by specific facts and circumstances, substantially outweighs prejudice and reasonable written notice is given.
- Contradiction: Contradicting factual testimony. Extrinsic evidence barred if purely collateral.
- Sensory or Mental Impairment: Poor eyesight, lighting, intoxication, distance. Challenges perception reliability without accusing witness of moral dishonesty!
Rehabilitation (Rule 801(d)(1)(B)) & Sequestration (Rule 615)
Responsive Rehabilitation: A party cannot bolster a witness before credibility is attacked. Rehabilitation must logically respond to the exact attack made (e.g., explaining an inconsistency on redirect; truthful character evidence only after truthfulness attacked).
Prior Consistent Statements (Rule 801(d)(1)(B)): If the declarant testifies and is subject to cross-examination, a consistent statement may be substantive evidence when offered either to rebut a charge of recent fabrication or improper influence or motive, or to rehabilitate credibility after another kind of attack. For the fabrication-or-motive route, the statement generally must predate the alleged motive or influence. The second route still requires a genuine rehabilitative fit; repetition alone does not bolster credibility.
Rule 615 Witness Sequestration: At a party's request, the court must exclude witnesses from the courtroom; it may also do so on its own. The rule does not authorize excluding a natural-person party, one properly designated representative of an entity party, a person shown essential to presenting a claim or defense, or a person authorized by statute. Courtroom exclusion alone does not forbid later disclosure or access to testimony, but the court may enter additional orders doing so.
Master List of Witness & Expert Examination Traps
• Do not collapse competency and credibility into one question (memory lapses go to weight, not competency).
• Do not confuse refreshing recollection with recorded recollection (if memory returns, witness testifies; if not, qualifying record is read).
• Do not assume confidence equals Rule 602 personal knowledge.
• Do not allow lay witnesses to give specialized technical or scientific opinions under Rule 701.
• Do not assume an expert's impressive general credentials qualify them for an unrelated specific inquiry.
• Do not confuse Daubert scientific reliability with "fit" to the actual issues in the dispute.
• Do not allow experts to instruct the jury on the law or state legal conclusions.
• Do not generalize Rule 608(b)'s character-purpose extrinsic-evidence bar to bias; test bias evidence under relevance, Rule 403, and proper procedure.
• Do not assume all felony convictions are automatically admissible under Rule 609; distinguish Rule 609(a)(2) elemental dishonesty or false statement, the applicable felony balancing test, and the more-than-ten-year rule.
• Do not bolster a witness before an attack has occurred.
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