Discovery and evidence

Expert Witness

An expert witness is someone qualified by knowledge or experience who is allowed to give opinion testimony to help the jury understand technical evidence.

Retained experts must produce a written report containing their opinions, the basis for them, the data considered, their qualifications, prior testimony, and compensation. Missing the disclosure deadline in the scheduling order can mean losing the expert entirely.

Admissibility is screened by the judge. The court acts as gatekeeper, asking whether the expert is qualified, the methods are reliable, and the opinion fits the facts of the case.

Non-retained experts are treated differently. A treating physician or an in-house engineer may testify without a full written report, but the party still has to disclose the subject matter and a summary of the expected opinions. Experts also must supply a list of every case in which they testified over the previous four years, which is how opposing counsel finds prior transcripts and contradicting opinions.

How it appears on a docket

EXPERT DISCLOSURE of Dr. L. Amari, forensic accountant, with report on damages, served pursuant to Rule 26(a)(2)(B).

Governing rule

Fed. R. Civ. P. 26(a)(2); Fed. R. Evid. 702

Related terms

  • Daubert MotionA Daubert motion asks the judge to exclude an expert's testimony because the methodology is unreliable or the opinion will not help the jury.
  • DiscoveryDiscovery is the pretrial process in which each side must hand over the evidence and information relevant to the case.

More on discovery and evidence

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