expert witness disclosure

Parties to a lawsuit have a duty to disclose to opposing counsel the identity of their expert witnesses they intend to call at trial, and to make a fair disclosure of the expert’s views. See Payne v. S.S. Nabob, 302 F.2d 803, 807 (3d Cir. 1962), cert denied 371 U.S. 870 (1962).

In federal courts, expert witness disclosure is governed by Article VII of the Federal Rules of Evidence. Under Rule 26(a)(2) of the Federal Rules of Civil Procedure, a party must disclose to the other parties the identity of any witness it may use at trial to present expert witness testimony pursuant to Federal Rule of Evidence 702, 703, or 705. Unless otherwise stipulated or ordered by the court, the expert witness disclosure in federal court must be accompanied by an expert witness report—prepared and signed by the witness. In the absence of a court order, disclosure pursuant to Rule 26 must be made 90 days before trial. 

Parties making disclosures have a duty to supplement or correct a disclosure if the party learns that in some material respects disclosure was incomplete or incorrect. With respect to testimony of an expert witness from whom a report is required, the duty extends to both information contained in the report and to information provided through a deposition of the expert. All supplemental disclosures must be made within the time set under Rule 26(a)(3).

The state rules regarding expert witness disclosure vary by jurisdiction. See State Civil Procedure Rules. This includes differences in the procedures for demanding the exchange of expert witnesses, their designation, the listing of publications, and the necessity of expert reports. All states in some form require that the parties provide a brief statement of the general substance of the testimony that the expert is expected to give. Enough information must be given to put the opposing party on notice of expert’s testimony, so that opposing party can select its own expert and meaningfully prepare to depose the designated expert and examine him/her at trial. The courts have the ability to sanction a party, and exclude expert witnesses who are not property disclosed. 

[Last updated in August 2023 by Jim Robinson Esq., JurisPro Expert Witness Directory]