The Expert Witness: A Key Player in Medical Malpractice Cases

By: Rafi Cheema, Esq., MLMIC Legal Department

Medical malpractice cases often hinge on complex medical issues that require expert interpretation. Expert witnesses, highly qualified professionals in specific medical fields, play a crucial role in these cases. They provide impartial, expert opinions that help juries and judges understand the nuances of medical care and identify potential negligence.

Let’s take a closer look at medical malpractice experts.

Role of Expert Witnesses in Medical Malpractice Cases

In order to establish medical malpractice, the plaintiff must prove (1) the applicable standard of care; (2) that the defendant doctor/facility/provider deviated from the accepted standard of care; and (3) that the deviation proximately caused the plaintiff’s alleged injuries. In almost all medical malpractice cases, the plaintiff must proffer expert testimony to establish these essential elements of their cause of action. The role of the plaintiffs’ expert witness, therefore, is essentially to delineate and explain the applicable standard of care and how the defendants fell short of it and thereby caused the alleged injuries. In turn, the defense will typically refute the plaintiff’s expert proof with a defense expert, who may opine that the care complied with the standard of care, that there was no departure and/or there are no causally related damages. If the named defendant is a physician, the defendant physician may also act as his/her/their own expert, though this is rare. Thus, the expert witness is the key to a medical malpractice case for the plaintiff and the defense.

Defining an Expert Witness

So, who can qualify as a “medical expert” in a medical malpractice case? Can a Grey’s Anatomy fan who has become well versed with the medical world or a medical student waiting to graduate be considered a “medical expert”? No. A medical expert must possess “the requisite skill, training, education, knowledge or experience from which it can be assumed that the rendered opinion is reliable.” Holland v. Cayuga Med. Ctr. at Ithaca, Inc., 195 A.D.3d 1292, 1294, 150 N.Y.S.3d 372 (2021). Therefore, depending on the specialty of the defendant and the facts of the case, a medical expert could be a qualified physician, surgeon, nurse or some other type of medical provider. It is not required that an expert be in the same specialty as the defendant physician as long as the expert can establish that she/he/they are familiar with the standard of care. An expert from a different specialty may also be necessary to address the issue of damages. For example, in a failure to diagnose cancer case, the liability expert will likely be the same specialty as the defendant provider, but the causation expert may be an oncologist who can opine as to the effect of the delayed diagnosis.

Significance of an Expert Witness

On the plaintiff side, the role of the expert begins right from the outset of the medical malpractice case. Pursuant to New York Civil Practice Law and Rules Section 3012-a, plaintiffs are required to file a Certificate of Merit with the original Complaint. So, what is a Certificate of Merit? A Certificate of Merit is essentially a document certifying that the plaintiffs’ attorneys have consulted with a medical expert who has arrived at the conclusion that the plaintiffs’ medical malpractice action has merit. As part of the Certificate of Merit, the medical expert must also confirm that there is a reasonable basis for the lawsuit, that the plaintiffs’ healthcare provider deviated from acceptable medical practices and that deviation resulted in the alleged injuries to the plaintiff. If the plaintiffs do not submit a Certificate of Merit showing that the defendants deviated from the standard of care, the defense may seek dismissal of the case.

Does obtaining the Certificate of Merit mean that the plaintiffs have proven their case? No, the filing of the Complaint along with the Certificate of Merit is just the beginning of the case. In fact, filing the Certificate of Merit is simply a prerequisite to bringing forth a medical malpractice case, after which the discovery portion of the case begins, wherein evidence is gathered by both sides to prove their positions.

Later, at the time of trial, the expert witness will be called upon to give expert testimony. The purpose of the expert witness in testifying at trial is to help the jury understand the case from a medical point of view. Prior to trial, the expert’s identity does not have to be disclosed. As part of the discovery phase of the case, both parties are required, as per New York Civil Practice Law and Rules Section 3101, to disclose the expert’s education and experience as well as the sum and substance of the expected testimony the expert witness will give at the time of trial. As part of expert testimony, the expert witness may provide his/her/their opinion on the medical records, treatment plans and standards of care under consideration in the case.

Oftentimes, a medical malpractice case that goes to trial is colloquially referred to as a “battle of the experts,” as both the plaintiff and defendant have their own respective experts who testify at trial, giving competing opinions. The jury then decides which expert’s testimony they will accept, in whole or in part, and which testimony to reject, in whole or in part.

The premise that both sides introduce experts with competing opinions might sound simple at the outset, but it can be complicated. After all, a jury of laypersons will ultimately decide the credibility of the expert testimony. Therefore, the job of any skilled medical malpractice attorney, whether on the plaintiffs’ side or the defendants’ side, is to be able to skillfully cross-examine, rebut and impeach the expert on the other side. Furthermore, there is no formulaic approach that can predict success. Just because you have a competent and qualified expert ready to testify on your behalf does not necessarily mean that you will be “successful” at trial. It all depends on the jury – whether they decide to accept your expert’s testimony, how much of it they accept and how much of it they reject.

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This document is for general purposes only and should not be construed as medical or legal advice. This document is not comprehensive and does not cover all possible factual circumstances. Because the facts applicable to your situation may vary, or the laws applicable in your jurisdiction may differ, please contact your attorney or other professional advisors for any questions related to legal, medical or professional obligations, the applicable state or federal laws or other professional questions.