Expert witnesses play an essential role in determining if medical negligence has occurred. In some states, expert witness testimony is used to evaluate the merits of a medical malpractice claim before filing legal action. During the trial, courts rely on the testimony of expert witnesses in order to determine if the standard of care that can be applied to the malpractice suit has been breached, thereby causing an injury. The expert witness has three main roles in a medical malpractice case:

• 1. To explain the standard of care that is relevant to the case


• 2. To identify any breaches of the standard of care on the part of the defendant, and


• 3. Provide an opinion on whether those breaches are the most likely cause of the plaintiff's injury.

Expert witnesses are allowed to compare the applicable medical standards of care with the facts of a given medical malpractice case and interpret whether the evidence indicates a deviation from the standards of care. He or she may also be asked to evaluate whether the factual testimony provided by other witnesses suggests a deviation from the accepted standard of care. The expert witness may also testify about the current clinical state of the plaintiff in order to assist in the process of determining fair damages.

The testimony of an expert witness should be reliable, objective, accurate, and provide a truthful analysis of the standard of care. Some states have laws that set forth minimum qualifications for expert witnesses, while others have no special requirements regarding who can provide expert testimony in medical malpractice cases.