Types of Expert Witnesses

Thanks to dramas on television and lawsuits in the news every day, you are probably familiar with what an expert witness does. However, you may not know what it takes to qualify as an expert or where the boundaries of their influence end.


Areas of Specialty

An attorney may hire a medical expert in a malpractice case, or a mental health expert to determine whether a defendant is fit to stand trial. Licensed individuals from professional service companies may also serve as expert witnesses. For example, if part of a structure collapses and someone is injured, an expert from a professional engineering firm may be asked to testify as to the safety of the building’s design. Forensic experts evaluate evidence in criminal cases. These are just a few of the scenarios in which an expert witness might become involved.


As written in the federal rules of evidence, an expert witness is someone who has the skills, knowledge, education or experience to be considered an expert in a particular area. An expert witness should also have an unimpeachable reputation, as sometimes attorneys will attempt to discredit the expert if his opinion is not favorable for their client.

Boundaries of Influence

The purpose of an expert witness is not only to review the evidence but also to explain it in a way that both the judge and jury can understand. Unlike a regular witness, an expert witness provides an opinion.  It must be honest and impartial and relate only to the specific points of the dispute. They may not provide additional evidence or give advice.

Expert witnesses testify in cases involving medicine, professional liability and forensics, just to name a few examples. Their role is to provide an independent opinion based on specific knowledge as it relates to a court case, and nothing more. A vital function of an expert witness is to explain complicated details in a way that makes them accessible to the average person.

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