Sometimes, the facts in a case are technical or specialized and the lay person does not understand. If the judge or jury needs to have the facts explained by a professional, then either party may call in an expert witness to provide the information.
However, the courts have rules for the qualifications of expert witnesses as well as the process of providing the testimony.
Qualifications of an expert witness
According to the Cornell University Law School’s Legal Information Institute, Rule 702 of the Federal Rules of Evidence states that the witness must have the education, training, skill, experience or knowledge that qualifies him or her as an expert in the matter at hand. Not only could a doctor or architect serve as an expert witness, but also some people who fall under the label of “skilled” witnesses because they have specialized knowledge, even if it is not necessarily technical or scientific.
The court approves expert witnesses before the trial begins.
Admission of testimony
The court will allow the testimony if it is essential to understanding key points in the case for the judge or jury. To back up the claims he or she plans to make, the expert must show that he or she based the testimony on sufficient information, used reliable methods and principles and applied these to the facts of the case.
Courts may assess how reliable an expert’s testimony may be by considering:
- Whether the method or theory behind it has been the subject of peer review or publication
- Whether there is a known rate of error when applying the theory
- Whether there are standards and controls in use
- Whether the scientific community has accepted it
The judge has the authority to determine how in-depth the reliability proceedings are for the expert witness’s qualifications and testimony.