What Is an Expert Witness?


It is common for attorneys to bolster a case with testimony from an expert witness. Expert witness services are available to prosecutors and defendants alike. They serve to enhance the credibility of testimony and support the evidence in order to help a judge or jury render a just decision.

What Makes Expert Witnesses Different From Others?

It may go without saying, but expert witnesses have specialized knowledge and expertise about a particular topic that is relevant in some ways to the court proceedings. Rather than testifying to things that he or she personally observed, an expert witness offers his or her professional opinion relating to the facts of the case on the basis of previous experience and education. They represent an exception to the rule that witness testimony must be purely factual and not include personal opinions.

What Types of Expert Witnesses Are There?

Professionals with advanced knowledge on many different subjects may serve as expert witnesses. The type of expert witness required depends in part upon the case itself and the facts involved. However, certain types of expert witnesses are more common in courtrooms than others. These include professionals in psychology and medicine, computer forensics, civil and criminal litigation, and finance.

Who Can Be an Expert Witness?

If a person has education and experience with a certain topic that extends beyond general knowledge, then theoretically, he or she can qualify as an expert witness. However, the attorney who obtains the services of an expert witness should be prepared to demonstrate his or her qualifications by citing certifications, advanced degrees, and/or years of experience.

In addition to being qualified, an expert witness must be reliable. In other words, his or her honesty, integrity, and trustworthiness must be beyond reproach.

Though it is unconventional and may leave an unfavorable impression on the judge and/or jury, there is no law that says that a defendant cannot offer expert testimony on his or her own behalf, provided he or she otherwise qualifies as a expert witness.