§ 25.03 OPINION BASED ON ADMITTED EVIDENCE ("RECORD FACTS")

• Jurisdiction: United States

§ 25.03. OPINION BASED ON ADMITTED EVIDENCE ("RECORD FACTS")

Under Rule 703, an expert may base an opinion on facts or data that the expert has been made aware of at trial, typically through a hypothetical question. Although this method of eliciting expert opinion is still available,² the Federal Rules do not require its use. In addition to the standard hypothetical question, a "modified" hypothetical (my phrase) may be used. Of course, if the expert has personal knowledge of data, there is no need to resort to a hypothetical question.

[A] Hypothetical Questions

During direct examination, the attorney may ask the expert to assume certain facts as true and then ask if the expert has formed an opinion based on those assumed facts. If the expert replies "yes," she may give an opinion.³ The assumed facts must be adduced through other evidence at some point during the trial. In short, these facts must be in the record.⁴

The hypothetical question serves several purposes. First, it expands the parties' access to expert testimony because they are no longer limited to experts with personal knowledge. Outside experts can be brought into the case and supplied with the relevant facts through hypothetical questions. Second, the hypothetical question compels the expert to disclose the bases before giving the opinion, thus informing the jury of the facts upon which the opinion rested. These facts are often controverted. If the jurors reject them, the jury should also reject the opinion. Hypothetical questions also provide the opposing party with an opportunity to object if the basis includes facts not admitted in evidence (i.e., nonrecord facts).

Material facts. Some courts require that the hypothetical question contain all the "material" facts.⁵ Otherwise, there is a risk that the jury may be misled because the offering party — by omitting some facts — could elicit an opinion grounded on a faulty basis. Nevertheless, many courts reject this requirement and instead allow the cross-examiner to change the hypothetical question by including additional facts. Moreover, the trial judge retains discretion under Rule 408⁶ and may require the examiner to rephrase an unfair or misleading hypothetical question.⁷

Disputed bases. A dispute concerning the underlying facts assumed in the hypothetical question does not preclude admissibility. Typically, this dispute involves a jury issue.

Criticism of hypothetical questions. Although it has advantages, the hypothetical question has been extensively criticized. Wigmore noted that "its abuses have become so obstructive and nauseous that no remedy short of extirpation will suffice. It is a logical necessity, but a practical incubus; and here...