What Is An Expert Witness?

This blog deals with big personal injury lawsuits across the country. These lawsuits typically involve class actions, multidistrict litigation, and mass torts against corporations for their defective products, medications, or their general negligence. But we also talk about motor vehicle accident and malpractice claims, too.  For all of these cases, you are almost invariably going to need an expert to testify if you want to get your case to a jury.  Experts are obviously different from the typical fact witness. This post should give you a basic understanding of the nuances of expert witnesses and testimony.

What Is a Witness?

Before we can dive into the nuances of expert witnesses though, I think it is appropriate to discuss how witnesses work in general. In court, you prove your case by eliciting testimony of witnesses. Your lawyer cannot just waltz in front of the jury and deliver a speech about the facts of the case and the legal argument; you need witnesses to introduce and corroborate the information that a lawyer is trying to bring out. This is accomplished via direct examination (let’s call it “friendly examination”) and cross-examination (“unfriendly examination” for this one). Direct examination is “friendly” because the witness being questioned is considered a witness for the party that called them. This means that questioning (usually) involves the lawyer simply attempting to get what is stored in the witness’s brain copied to the court record. An example of a question on direct examination would be something like “Dr. Smith, can you describe the injuries that Mr. Doe sustained?” Direct examination is generally non-hostile and does not involve credibility attacks.

That is where cross-examination comes in. Cross-examination is the other side’s opportunity to question your witness. The rules are a little different here; lawyers are allowed to ask leading questions and attack the credibility of the witness. That is the goal of cross-examination: impeachment. And no, I am not talking about Richard Nixon or Bill Clinton. Impeachment is the process of casting doubt upon the testimony of a witness. A question on cross-examination may look something like “Dr. Smith, isn’t it true that you and Mr. Doe are childhood friends?” That question is obviously trying to cast doubt upon Dr. Smith, suggesting that his testimony is not as impartial because of his association with Mr. Doe.

So What Makes a Witness an Expert?

An expert, in the legal sense, in anyone who has specialized knowledge in a particular field beyond that of your average Joe. To put it into perspective, take a car accident case where the issue is whether the light at an intersection was red or green. You can rely on a layperson eyewitness to say whether they saw if the light was green or red. However, what if the issue is whether a brake failure contributed to running the red light? Your lay witness cannot exactly attest to the mechanics of brakes. That is where an expert comes in.

Experts are hired by litigants to testify about issues that require technical or scientific knowledge. The rules are a little different for experts, however. While your non-expert witness can generally only attest to facts, expert witnesses are allowed to give their opinion on matters. They can even bring in things that would usually be considered hearsay to back up their opinions.

Of course, the court has to “qualify” an expert before they can do all of that. I could not just walk up to the stand and claim to be an expert in surgery because I caught a few reruns of Grey’s Anatomy. The court will examine the credentials of the witness to determine whether he or she is actually an expert and then grant or deny them the ability to offer expert testimony.

Expert Witnesses and Big Personal Injury Cases

Expert witnesses are a must for pretty much every personal injury case that involves litigants contesting the severity or cause of an injury. For example, we talk a lot about cases involving dangerous pharmaceutical drugs on this blog. You would need an expert witness to testify about how the drug caused the injury at issue.  Advanced chemistry as it pertains to medicine is a topic so complex that a court needs an expert to explain it to them. That is really the core purpose of an expert.

Of course, the other side will have their experts as well to contradict your experts.  Each side pays their experts (usually a ton of money) to testify, so one way to draw the expert’s truthfulness into question is to put out in the open how much money they are being paid by the party.  I settled a case two weeks ago where the main expert against us makes $1.2 million a year testifying in car accident claims for insurance companies. Chances are, a party will not pay an expert a ridiculous sum of money if they know that they will testify in a way that hurts their case. Experts are typically deposed as well; which gives both sides a chance to know what the experts will say.

You may have heard of a trial being labeled as a “battle of the experts.” These are cases that rely almost solely upon the testimony of expert witnesses and both sides’ experts are offering contradictory, or maybe even diametrically opposed testimony. These are tougher for juries to decide because they are being peppered with conflicting information and are forced to make a determination based on credibility.

Expert witnesses are a huge part of personal injury litigation. They are also one of the most expensive aspects of trying a big personal injury case. They’re important to sorting out complex matters, though, is another necessary reality of personal injury litigation.