Federal Rules of Evidence – Rule 703
(through July 14, 2022)
Unlike lay witnesses, experts can base testimony on info beyond their own observations. Experts can even base testimony on inadmissible info, if reasonably customary to rely on info like that in their field. But experts can only disclose inadmissible, relied-upon info if prejudicial risk is substantially outweighed by probative value.
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.
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Selected Committee Notes
Facts or data upon which expert opinions are based may, under the rule, be derived from three possible sources. The first is the firsthand observation of the witness, with opinions based thereon traditionally allowed. A treating physician affords an example. Rheingold, The Basis of Medical Testimony, 15 Vand.L.Rev. 473, 489 (1962). Whether he must first relate his observations is treated in Rule 705. The second source, presentation at the trial, also reflects existing practice. The technique may be the familiar hypothetical question or having the expert attend the trial and hear the testimony establishing the facts. Problems of determining what testimony the expert relied upon, when the latter technique is employed and the testimony is in conflict, may be resolved by resort to Rule 705. The third source contemplated by the rule consists of presentation of data to the expert outside of court and other than by his own perception. In this respect the rule is designed to broaden the basis for expert opinions beyond that current in many jurisdictions and to bring the judicial practice into line with the practice of the experts themselves when not in court. Thus a physician in his own practice bases his diagnosis on information from numerous sources and of considerable variety, including statements by patients and relatives, reports and opinions from nurses, technicians and other doctors, hospital records, and X rays. Most of them are admissible in evidence, but only with the expenditure of substantial time in producing and examining various authenticating witnesses. The physician makes life-and-death decisions in reliance upon them. His validation, expertly performed and subject to cross-examination, ought to suffice for judicial purposes. Rheingold, supra, at 531; McCormick §15. A similar provision is California Evidence Code §801(b).
The rule also offers a more satisfactory basis for ruling upon the admissibility of public opinion poll evidence. Attention is directed to the validity of the techniques employed rather than to relatively fruitless inquiries whether hearsay is involved. See Judge Feinberg’s careful analysis in Zippo Mfg. Co. v. Rogers Imports, Inc., 216 F.Supp. 670 (S.D.N.Y. 1963) See also Blum et al, The Art of Opinion Research: A Lawyer’s Appraisal of an Emerging Service, 24 U.Chi.L.Rev. 1 (1956); Bonynge, Trademark Surveys and Techniques and Their Use in Litigation, 48 A.B.A.J. 329 (1962); Zeisel, The Uniqueness of Survey Evidence, 45 Cornell L.Q. 322 (1960); Annot., 76 A.L.R.2d 919.
If it be feared that enlargement of permissible data may tend to break down the rules of exclusion unduly, notice should be taken that the rule requires that the facts or data “be of a type reasonably relied upon by experts in the particular field.” The language would not warrant admitting in evidence the opinion of an “accidentologist” as to the point of impact in an automobile collision based on statements of bystanders, since this requirement is not satisfied. See Comment, Cal.Law Rev.Comm’n, Recommendation Proposing an Evidence Code 148–150 (1965).
703 has been amended to emphasize that when an expert reasonably relies on inadmissible information to form an opinion or inference, the underlying information is not admissible simply because the opinion or inference is admitted. Courts have reached different results on how to treat inadmissible information when it is reasonably relied upon by an expert in forming an opinion or drawing an inference. Compare United States v. Rollins, 862 F.2d 1282 (7th Cir. 1988) (admitting, as part of the basis of an FBI agent’s expert opinion on the meaning of code language, the hearsay statements of an informant), with United States v. 0.59 Acres of Land, 109 F.3d 1493 (9th Cir. 1997) (error to admit hearsay offered as the basis of an expert opinion, without a limiting instruction). Commentators have also taken differing views. See, e.g., Ronald Carlson, Policing the Bases of Modern Expert Testimony, 39 Vand.L.Rev. 577 (1986) (advocating limits on the jury’s consideration of otherwise inadmissible evidence used as the basis for an expert opinion); Paul Rice, Inadmissible Evidence as a Basis for Expert Testimony: A Response to Professor Carlson, 40 Vand.L.Rev. 583 (1987) (advocating unrestricted use of information reasonably relied upon by an expert).
When information is reasonably relied upon by an expert and yet is admissible only for the purpose of assisting the jury in evaluating an expert’s opinion, a trial court applying this Rule must consider the information’s probative value in assisting the jury to weigh the expert’s opinion on the one hand, and the risk of prejudice resulting from the jury’s potential misuse of the information for substantive purposes on the other. The information may be disclosed to the jury, upon objection, only if the trial court finds that the probative value of the information in assisting the jury to evaluate the expert’s opinion substantially outweighs its prejudicial effect. If the otherwise inadmissible information is admitted under this balancing test, the trial judge must give a limiting instruction upon request, informing the jury that the underlying information must not be used for substantive purposes. See Rule 105. In determining the appropriate course, the trial court should consider the probable effectiveness or lack of effectiveness of a limiting instruction under the particular circumstances.
The amendment governs only the disclosure to the jury of information that is reasonably relied on by an expert, when that information is not admissible for substantive purposes. It is not intended to affect the admissibility of an expert’s testimony. Nor does the amendment prevent an expert from relying on information that is inadmissible for substantive purposes.
Nothing in this Rule restricts the presentation of underlying expert facts or data when offered by an adverse party. See Rule 705. Of course, an adversary’s attack on an expert’s basis will often open the door to a proponent’s rebuttal with information that was reasonably relied upon by the expert, even if that information would not have been discloseable initially under the balancing test provided by this amendment. Moreover, in some circumstances the proponent might wish to disclose information that is relied upon by the expert in order to “remove the sting” from the opponent’s anticipated attack, and thereby prevent the jury from drawing an unfair negative inference. The trial court should take this consideration into account in applying the balancing test provided by this amendment.
This amendment covers facts or data that cannot be admitted for any purpose other than to assist the jury to evaluate the expert’s opinion. The balancing test provided in this amendment is not applicable to facts or data that are admissible for any other purpose but have not yet been offered for such a purpose at the time the expert testifies.
The amendment provides a presumption against disclosure to the jury of information used as the basis of an expert’s opinion and not admissible for any substantive purpose, when that information is offered by the proponent of the expert. In a multi-party case, where one party proffers an expert whose testimony is also beneficial to other parties, each such party should be deemed a “proponent” within the meaning of the amendment.
Key Rules (MBE/MEE)
- FRE 103 – Evidence Rulings
- FRE 104 – Preliminary Questions
- FRE 105 – Limiting How Evidence may be Used
- FRE 106 – Completeness Rule
- FRE 201 – Judicial Notice
- FRE 301 – Presumptions
- FRE 401 – Relevance
- FRE 402 – Irrelevant = Inadmissible
- FRE 403 – Excluding the Prejudicial, Confusing, etc.
- FRE 404 – Character Evidence
- FRE 405 – Proving Character
- FRE 406 – Habit, Routine
- FRE 407 – Subsequent Remedial Measures
- FRE 408 – Compromise Negotiations
- FRE 409 – Offers to Pay Expenses
- FRE 410 – Pleas, Related Statements
- FRE 411 – Liability Insurance
- FRE 412 – Victim’s Sexual Predisposition
- FRE 413, 414, 415 – Other Sex-Related Rules
- FRE 501 – Privilege in General
- FRE 502 – Attorney-Client Privilege, Work-Product Doctrine
- FRE 601 – Witness Competency
- FRE 602 – Personal Knowledge
- FRE 605 – Judge as Witness
- FRE 606 – Juror as Witness
- FRE 607 – Impeachment
- FRE 608 – Honest, Dishonest Character
- FRE 609 – Evidence of Criminal Conviction
- FRE 610 – Religious Beliefs
- FRE 611 – Mode, Order of Evidence
- FRE 612 – Recollection Refreshed
- FRE 613 – Prior Statements
- FRE 614 – Court Witness Examination
- FRE 615 – Excluding Witnesses
- FRE 701 – Non-Expert Opinion
- FRE 702 – Expert Opinion
- FRE 703 – Bases of Expert Opinion
- FRE 704 – Ultimate Issue
- FRE 705 – Disclosing Underlying Data
- FRE 801 – Hearsay Defined
- FRE 802 – Rule Against Hearsay
- FRE 803 – Strong Hearsay Exceptions
- FRE 804 – Weak Hearsay Exceptions
- FRE 805 – Double Hearsay
- FRE 806 – Impeaching Hearsay Declarants
- FRE 807 – Residual Hearsay Exception
- FRE 901 – Authentication, Identification
- FRE 902 – Self-Authenticating Evidence
- FRE 1001 – Original Defined
- FRE 1002 – Original Sometimes Required
- FRE 1003 – When Copies Generally Admissible
- FRE 1004 – Other Times Admissible
- FRE 1005 – Public Record Copies Often Admissible
- FRE 1006 – Summaries
- FRE 1007 – Acknowledged Content
- FRE 1008 – Functions of Court, Jury
- FRE 1101 – Rules’ Applicability