Expert Witness in the United States

A person who has special knowledge of a subject matter about which he or she is to testify in a legal proceeding. An expert witness is a person who has knowledge or expertise not usually found in the average person. Educational degrees may provide the basis for a person being an expert witness, but special skill or knowledge based on experience may also qualify a person as an expert witness. Whether a person possesses the necessary qualifications to serve as an expert witness is a determination of the trial court. The testimony of an expert witness is based directly on his or her status as an expert. A lay witness, on the other hand, provides testimony based on personal knowledge of facts at issue in the case.

See Also

Witness (Civil Process).

Analysis and Relevance

Expert witnesses are crucial in particular kinds of cases. A psychiatrist, for example, is key in attempting to establish an insanity or diminished capacity defense to criminal charges. Similarly, geologists or chemists with particular expertise in water quality may be pivotal witnesses in a case where plaintiffs are seeking damages from a defendant who allegedly contaminated a water supply with discharged industrial waste. Unlike the lay witness, whose testimony is confined to what he or she knows directly about the fact situation, the expert witness can offer expert testimony. This allows the expert to offer opinions and conclusions drawn from their expertise.

Notes and References

1. Definition of Expert Witness from the American Law Dictionary, 1991, California

Practical Information

Note: Some of this information was last updated in 1982

A person selected because of knowledge or skill to examine, estimate, and ascertain things and to make a report of his or her opinion at trial. An expert can draw from facts inferences that a layman could not make, and in this way the expert aids the jury. The facts upon which the expert’s opinion is based may have been personally observed by the expert or incorporated in a hypothetical question put to him or her. Whether a witness is qualified to speak as an expert is a preliminary question of fact to be determined by the trial court. A few examples of specialized fields where an expert’s testimony would be necessary are medicine, ballistics, chemical analysis, psychiatry, and engineering.

(Revised by Ann De Vries)

What is Expert Witness?

For a meaning of it, read Expert Witness in the Legal Dictionary here. Browse and search more U.S. and international free legal definitions and legal terms related to Expert Witness.

Pathologist as Expert Witness; Malpractice Considerations

This section examines the Pathologist as Expert Witness; Malpractice Considerations subject in its related phase of trial. In some cases, other key elements related to trials, such as personal injury, business, and criminal litigation, are also addressed.

Cause of Action for Negligence or Malpractice of Expert Witness: an Overview

This section examines this type of action. This subject identifies the various elements of the Cause of Action for Negligence or Malpractice of Expert Witness, offering a practical approach to the litigation issues of this cause of action. See also the entry about legal risks.

Expert Witness

Real Property Expert Witness Filings RP-EW-DOCS Database

This is a database related to interests in and transfers of real estate, in the following material: Case Law, Briefs, Trial Filings, and Jury Verdicts. A description of this real estate database is provided below:

Selected reports, affidavits, depositions, and transcripts of trial testimony of expert witnesses in cases from selected state and federal trial courts that relate to interests in real property. Coverage begins with 1996.

Further information on United States legal research databases, including real property databases, are provided following the former link.

Resources

Further Reading

• Are court-appointed experts the solution to the problems of expert testimony?, Champagne, Anthony, Easterling, Danny, Shuman, Daniel W., Tomkins, Alan J., and Whitaker, Elizabeth, 84: 178-183 (Jan.-Feb. '01, AJS Judicature)
• The changing nature of psychological expert testimony in child custody cases, Wah, Carolyn R., 86: 152-161 (Nov.-Dec. '02, AJS Judicature)
• Expert Witnesses in the Courts: An Empirical Examination, Champagne, Anthony, Shuman, Daniel W., and Whitaker, Elizabeth, 76: 5-10 (Jun.-Jul. '92, AJS Judicature)
• Forensic psychiatric diagnosis unmasked, Greenberg, Stuart A., Shuman, Daniel W., and Meyer, Robert G., 88: 210-215 (Mar.-Apr. '05, AJS Judicature)
• The legal system's use of epidemiology, Bryant, Arthur H. and Reinert, Alexander A., 87: 12-21 (July-Aug. '03, AJS Judicature)
• The legal system's use of epidemiology: Some clarification, Korzeniewski, Steven James, 88: 137-139, 144 (Nov.-Dec. '04, AJS Judicature)
• The problems of applying Daubert to psychological syndrome evidence, Richardson, James T., Ginsburg, Gerald P., Gatowski, Sophia I., and Dobbin, Shirley A., 79: 10-16 (July-Aug. '95, AJS Judicature)
• The Use And Misuse Of Expert Evidence In The Courts (panel discussion), Discussion, Panel, 77: 68-76 (Sep.-Oct. '93, AJS Judicature)
• The Use of Court-Appointed Experts in Federal Courts, Cecil, Joe S. and Willging, Thomas E., 78: 41-46 (Jul.-Aug. '94, AJS Judicature)
• What Can the American Adversary System Learn from an Inquisitorial System of Justice? (query), Strier, Franklin, 76: 109-111, 161-162 (Oct.-Nov. '92, AJS Judicature)