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Witness vs. Expert Witness: Are There Any Major Differences?

Witness testimonies play an important role in deciding the outcome of a personal injury case. However, not all witnesses are equal: a very important line can be drawn between an ordinary witness and an expert witness. Both witnesses offer their knowledge and accounts, but their qualifications, preparation, and intended impact differ significantly.

An ordinary witness is normally a person who was present when the accident occurred. They can provide first-hand testimony and details based on their personal knowledge and experience. On the other hand, the expert witness does not base their testimony on firsthand knowledge. These people are experts in a certain field and provide informed opinions, analyses, and explanations to assist the judge and jury in understanding complex matters or evidence. A personal injury lawyer can help you understand the difference between these two types of witnesses and will use the right one at the right time to win your case.

What is a Witness?

Basically, a witness can be any person who is capable of offering some relevant testimony regarding the facts of a legal case. This may include eyewitnesses, victims, or any other person who is directly knowledgeable about the facts and things around which the litigation revolves.

Their task is quite simple: to relate and describe truthfully, to the best of their ability and recollection, what they saw, did, or knew. Witnesses must give truthful and impartial accounts in their statements and testimony. They cannot give opinions, make judgments, or draw subjective conclusions other than those that would be arrived at through their own immediate perceptions.

What is an Expert Witness?

Unlike a regular witness, the expert witness has no independent relation to the events of the case. Expert witnesses are retained by counsel for one of the parties and are asked to examine certain evidence or a subject matter as it relates to issues before the court through their specialized knowledge, training, or experience.

An expert is a highly qualified professional in a specific field, be it a doctor, an engineer, a forensic scientist, an economist, or more. For instance, a doctor may help analyze medical reports, an accident reconstruction expert may assist in the evaluation of evidence from a collision, or a forensic accountant may analyze financial damage claims. Experts can review case materials, conduct further research or testing if necessary, and make a professional opinion that is relayed to the court in the form of reports and testimony.

Qualifying an Expert Witness 

Expert witness testimony is admitted once a witness has been formally qualified based on the recognized standards. In practice, it often works by the judge reviewing and approving, in most cases, their educational background, credentials, professional experience, certifications, research, publications, and other indicators of expertise in the particular subject area. In other words, there must be sufficient demonstration of skill, knowledge, and qualification in the specialized discipline to be defined as an authority whose opinions would be valuable and relevant for the case.

Key Differences

Even though both types of witnesses have a significant role in the courtroom, there are some obvious differences:

Basis for Knowledge:  An eyewitness possesses experiential, firsthand knowledge of case events or circumstances. An expert witness possesses book knowledge and technical qualifications to evaluate case evidence and its implications based on the subject field.

Purpose: The eyewitness relates personal observations and accounts. An expert considers complex evidence from a standpoint of specialized knowledge and opinion in the determination for the judge or jury.

Allowed Testimony: An eyewitness is only allowed to relate firsthand experience. An expert is allowed to give opinions, judgments, hypotheses, and conclusions based on expert analysis of case materials.


Both the witness and the expert witness establish the most critical elements for developing a case strategy and enabling legal terms to present evidence most persuasively. Although both will be challenged on their credibility through cross-examination, the testimony and role of an expert witness hold more complexity, weight, and influence in shaping a judge’s or jury’s understanding and perception of key issues.