Pub. date: 2002 | Online Pub. Date: September 15, 2007 | DOI: 10.4135/9781412950664 | Print ISBN: 9780761922582 | Online ISBN: 9781412950664| Publisher:SAGE Publications, Inc.About this encyclopedia
Thomas E. Reed
An expert witness testifies to help judges and jurors find the truth and administer justice. To clarify scientific or technical issues, the expert brings special knowledge into court that laypersons are not expected to know. Unlike non-expert witnesses, whose testimony is limited to personal observations directly related to the case, expert witnesses are allowed to express and explain opinions by virtue of their knowledge, training, and experience. Judges must allow expert testimony if an individual's scientific, technical, or other knowledge is helpful and relevant to the case. However, reliance on expert witnesses does not always guarantee that the interests of truth and justice are served. Courts used expert, but nonscientific, knowledge as early as the fourteenth century, when juries composed of craftsmen or tradesmen often heard cases within their specialties. In other cases, jurors were scholars, engineers, and physicians. Ideas from science affected legal practice as early as the 1692 ...