The Importance of Expert Witnesses

The purpose of an expert witness in a trial is to aid the judge or the jury in determining the facts of a case. Often the facts of a case may be difficult to understand, especially for the average person, and those facts can range far outside the scope of their expertise and experience. As an example, in a medical malpractice case against a cardiac surgeon, it is unlikely that the average juror would be familiar with the correct procedures and techniques used in such a surgery, and likewise, the manner of deviation from those procedures and techniques. That is why expert witnesses can be a vital method for reaching jurors, as explanations from an expert can offer up the facts in a way that is more easily absorbed.

In personal injury cases, an expert is usually needed to evaluate the injury and long-term prognosis for the plaintiff and present those findings to a jury. Generally, this leads to the so called, “Battle of the Experts”, in which both the plaintiff and defendant hire expert witnesses to examine and testify about the severity of the plaintiff’s injury and the ultimate prognosis.

The examination done on behalf of the defendant is by way of an “Independent Medical Examination” or IME. However, these IME’s are generally anything but “independent” with the perhaps unsurprising results being that that defendant’s expert finds that the plaintiff’s injuries are much less severe than what the plaintiff’s physician believes. Often, the plaintiff’s expert is, in reality, the treating physician and knows the plaintiff much better than the defendant’s expert who only sees the plaintiff once and only for a brief examination. And so the experts square off in the courtroom, and the jury is left to discern whose arguments are strongest.

The damages portion of a personal injury case is not the only place where expert witnesses can be helpful. Expert witnesses are also useful in establishing the liability of the defendant with regard to a plaintiff’s claim of negligence. This is crucial in medical malpractice cases, but such testimony is also useful in other negligence actions, such as motor vehicle accidents, and slip and fall cases.

In motor vehicle accidents, an expert witness may be necessary to perform an accident reconstruction. Expert witnesses can determine and testify as to crucial evidence about the accident, such as the approximate speed the vehicles were traveling, how the vehicles collided, whether proper safety precautions were taken, such as breaking and allowing for proper distance between the vehicles.

Meanwhile, in a slip and fall case, an expert can testify as to whether the defendant took proper safety precautions to safeguard the plaintiff or should have warned the plaintiff of any dangers posed at the defendant’s establishment.

The timing as to when to hire an expert witness for a case is also crucial. The law in New York requires that all expert witnesses expected to testify at trial be disclosed in a timely fashion to the opposing party. This is done to avoid surprise at trial and to afford the other party an opportunity to procure an expert of their own choosing to rebut the testimony of the expert witness. This is why more often than not experts are hired well into the litigation process. After all, if a case is expected to settle quickly there is little desire to spend money on an expert whose testimony will never be needed.

However, when it comes to liability experts, hiring the expert early in the game has several advantages especially when liability is not clear-cut. A common tactic for defendants, especially in personal injury cases such as slip and falls, is to have the case dismissed through a summary judgment motion. A summary judgment motion asks the court to dismiss the case on the grounds that there is no liability as a matter of law due to some legal loophole, or element of negligence not being met. However, having an expert disclosed prior to the defendant’s making such a motion and preparing a report in opposition to such a motion is a useful and effective counter-measure to this defense tactic.

The use of expert witnesses can be a very effective tool for plaintiffs to aid and convince the jury to seeing their point of view and help them render a just and fair decision.


“The Importance of Expert Witnesses” was written by Michael B. Schulman, Managing Attorney.

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