Witnesses

A witness is a person who has information about facts relevant to a legal case or other inquiry and who provides testimony based on their observations or knowledge. Witnesses may give statements about what they saw, heard, or experienced, or may offer specialized expertise.

Common categories include lay (fact) witnesses, who describe events; and expert witnesses, who provide opinions based on training and study. Character witnesses speak to a person's reputation or character. Professionals such as investigators, scientists, or medical experts may be called as expert witnesses.

In courts, witnesses testify under oath, subject to cross-examination. The aim is to establish what happened. The credibility of a witness—consistency of statements, perception, memory, and potential biases—affects how their testimony is weighed. Hearsay and other rules limit what may be admitted, though there are exceptions.

Reliability concerns include memory decay, perception errors, stress, and suggestion. Courts seek corroboration from other evidence and may impeach a witness by introducing prior statements, demonstrating bias, or showing lack of expertise.

Procedures for witnesses include subpoenas to compel attendance, preparation with counsel, and recording of testimony in court or via deposition. Some systems provide protection for witnesses at risk, or allow anonymized or closed proceedings in sensitive cases.

Outside the courtroom, witnesses play a key role in journalism, historical research, inquiries, and investigations. Reports rely on witness accounts but must be evaluated alongside other sources, with attention to reliability and context.