Define: Expert Witness

An expert witness is an individual with specialised knowledge, skills, or experience in a particular field who is called upon to provide opinions or testimony in a legal proceeding based on their expertise. Expert witnesses play a crucial role in helping courts and juries understand complex technical, scientific, or professional matters relevant to a case. They may be engaged by either party to the litigation or appointed by the court, and their testimony is typically intended to assist the trier of fact in reaching a well-informed decision. Expert witnesses must meet certain qualifications and standards of reliability and credibility established by the court, and they are often subject to cross-examination by opposing parties to assess the validity of their opinions. The testimony of expert witnesses can significantly influence the outcome of legal proceedings, particularly in cases involving technical or specialised subject matter.

An expert witness is the person who has the knowledge or competence to offer an opinion in court on a specific topic including information of a legal, scientific or medical nature. The expert witness may also perform other tasks for a litigator over the course of the case including testifying at the deposition and trial, evaluating cases and reviewing documents.

Generally, the first task of the expert witness is to review information about the details of the case. The expert witness may also be asked to evaluate the basic facts of the case, help the attorney understand complicated issues and outline an initial strategy. If the lawyer is reviewing a personal injury claim they may want the expert witness to examine medical information about the plaintiff to determine if the lawyer should take the case or not.

A common deliverable for an expert witness is an expert report which outlines their opinion about the case. Expert witnesses may also have to provide testimony under oath by for both attorneys. Finally, they will be asked to testify at trial, under oath, and will likely have to face cross-examination by opposing counsel.

This site contains general legal information but does not constitute professional legal advice for your particular situation. Persuing this glossary does not create an attorney-client or legal adviser relationship. If you have specific questions, please consult a qualified attorney licensed in your jurisdiction.

This glossary post was last updated: 29th March, 2024.