Expert WitnessesIntroduction:

In civil litigation, expert witnesses have become a valuable and often necessary part of a case, and their opinions and testimony can pave the way to success at trial.

As some legal analysts explain, “Experts may not only be critical to the introduction of evidence (i.e. testimonial experts), but may also play a key role in the development, evaluation and preparation of the defense or prosecution of a case (i.e. consulting experts).” Douglas R. Heise & Gary C. Pinter, “When Do You Need An Expert Witness?”, presented at 25th Annual Claims Handling Seminar, Heyl, Royster, Voelker & Allen, May 20, 2010.

This article discusses some guidelines for when and why experts are so indispensable to litigators.


In terms of why expert testimony is necessary, both state and federal rules have agreed that such testimony is required “to introduce evidence regarding matters requiring ‘scientific, technical or specialized knowledge.’” Id.

Particularly in cases involving emerging technology, scientific advances, medical malpractice claims, and many mass torts, experts are needed to provide the evidence that a layperson cannot.

Moreover, such evidence assists judges and juries and often can be dispositive, in terms of a case’s outcome.

However, experts are not only needed to provide testimony and evidence for courts. They are also critical in their capacity as consultants on specialized matters.

Some attorneys explain that, for example, “ [A]n expert can assist in the understanding of factual complexities; in determining strengths and weaknesses of a case (your side and that of the opposition); in preparing written discovery; in preparing for depositions; in attacking opposing expert opinions; and assisting in trial strategy.” Id.

In terms of when experts are needed, there are numerous instances, even before attorneys are involved.

For example, a claims processor for an insurance company will require experts’ opinions to help assess the validity of a claim made by their clients’ or opposing parties. See id., e.g.

Many commentators have suggested that such experts be retained early and have even noted that it can be beneficial to have experts on call or as in-house advisors. See id., e.g.

In fields such as medical claims, toxic torts, and anything involving science or technology, experts’ involvement is typically required by different state laws.

For example, plaintiffs who wish to file a medical malpractice claim must have an expert opinion included in their complaint that supports their allegations. If they do not have that opinion, they are not permitted to file, or their claim will be summarily dismissed.

Other cases in many fields have similar requirements. Even when experts are not required to file a complaint, their evidence and opinions are frequently necessary to sustain a complaint and to overcome motions to dismiss.

Defense attorneys also have a need for the help and guidance that expert witnesses provide.

Moreover, it is to their benefit to retain such experts early, for a number of reasons.

Some lawyers tend to wait until the discovery period to consult an expert. This can be problematic, because then, such lawyers may not know whether their defense can be substantiated until it becomes too late.

In addition, by consulting experts as soon as a claim is made against their clients, defense attorneys can benefit by learning what views exist in the field and choose the best expert available.

Prolonging the engagement of expert witnesses allows the opposite side to be able to choose the best person first, and then attorneys may already be a step behind.

Even if an expert doesn’t agree with a litigator’s theory, retaining them as a consultant precludes the other side from doing so, and lawyers are not required to reveal consulting experts who don’t end up being further involved in the case or testifying.

Some instances where experts are called for include: product liability cases; auto accidents and reconstruction; malpractice cases that are medical, as well as those that involve other non-medical professionals, construction accidents and issues concerning defects or design; business litigation; insurance claims; and the aforementioned topics. See id, e.g.

In addition, experts are needed in any kind of civil litigation to provide evidence supporting or refuting particular components of a case.

For example, experts can help to establish or dispute causation, lost past income, lost future earnings, appropriate damages awards, lost profits, the value of a given asset, the extent of a disability or injury, future pain and suffering, and more. See id., e.g.


More and more experts are being retained in civil lawsuits, and that trend is expected to continue.

Attorneys in any field should consider how integral such witnesses are and retain them as early as possible.

In this way, litigators can increase the likelihood of success in the courtroom.