evidence

An expert may base an opinion on facts or data in the case that the expert has been made aware of or personally observed. If experts in the particular field would reasonably rely on those kinds of facts or data in forming an opinion on the subject, they need not be admissible for the opinion to be admitted. But if the facts or data would otherwise be inadmissible, the proponent of the opinion may disclose them to the jury only if their probative value in helping the jury evaluate the opinion substantially outweighs their prejudicial effect.

(a) In General — Not Automatically Objectionable. An opinion is not objectionable just because it embraces an ultimate issue.

(b) Exception. In a criminal case, an expert witness must not state an opinion about whether the defendant did or did not have a mental state or condition that constitutes an element of the crime charged or of a defense. Those matters are for the trier of fact alone.

Unless the court orders otherwise, an expert may state an opinion — and give the reasons for it — without first testifying to the underlying facts or data. But the expert may be required to disclose those facts or data on cross-examination.

Notes

(Pub. L. 93–595, §1, Jan. 2, 1975, 88 Stat. 1938; Mar. 2, 1987, eff. Oct. 1, 1987; Apr. 22, 1993, eff. Dec. 1, 1993; Apr. 26, 2011, eff. Dec. 1, 2011.)

Notes of Advisory Committee on Proposed Rules

(a) Appointment Process. On a party’s motion or on its own, the court may order the parties to show cause why expert witnesses should not be appointed and may ask the parties to submit nominations. The court may appoint any expert that the parties agree on and any of its own choosing. But the court may only appoint someone who consents to act.

Hearsay is not admissible unless any of the following provides otherwise:

• a federal statute;
• these rules; or
• other rules prescribed by the Supreme Court.

Notes

(Pub. L. 93–595, §1, Jan. 2, 1975, 88 Stat. 1939; Apr. 26, 2011, eff. Dec. 1, 2011.)

Notes of Advisory Committee on Proposed Rules

Hearsay within hearsay is not excluded by the rule against hearsay if each part of the combined statements conforms with an exception to the rule.

Notes

(Pub. L. 93–595, §1, Jan. 2, 1975, 88 Stat. 1943; Apr. 26, 2011, eff. Dec. 1, 2011.)

Notes of Advisory Committee on Proposed Rules

When a hearsay statement — or a statement described in Rule 801(d)(2)(C), (D), or (E) — has been admitted in evidence, the declarant’s credibility may be attacked, and then supported, by any evidence that would be admissible for those purposes if the declarant had testified as a witness. The court may admit evidence of the declarant’s inconsistent statement or conduct, regardless of when it occurred or whether the declarant had an opportunity to explain or deny it.

(a) In General. To satisfy the requirement of authenticating or identifying an item of evidence, the proponent must produce evidence sufficient to support a finding that the item is what the proponent claims it is.

(b) Examples. The following are examples only — not a complete list — of evidence that satisfies the requirement:

(1) Testimony of a Witness with Knowledge. Testimony that an item is what it is claimed to be.

A subscribing witness’s testimony is necessary to authenticate a writing only if required by the law of the jurisdiction that governs its validity.

Notes

(Pub. L. 93–595, §1, Jan. 2, 1975, 88 Stat. 1945; Apr. 26, 2011, eff. Dec. 1, 2011.)

Notes of Advisory Committee on Proposed Rules