Expert witnesses again

The qualification of expert witnesses in medical malpractice litigation presents a recurring challenge in New York courts, particularly when an expert seeks to testify regarding specialized areas of medical practice outside their primary field of practice. While New York law recognizes that physicians need not be specialists in a particular field to offer expert testimony regarding that field’s standards of care, courts have struggled to articulate a consistent standard for determining when a physician’s qualifications are sufficient to render reliable opinions in specialized areas of medicine. The tension between permitting broadly qualified medical experts and ensuring the reliability of specialized medical testimony has produced a body of case law that practitioners find difficult to navigate with certainty.

The foundational principle underlying expert qualification in New York is that the witness must possess skill, training, education, knowledge, or experience sufficient to support the assumption that their opinion is reliable. This standard, derived from common law principles and codified in the broader framework of expert testimony rules, requires more than a medical degree when the subject matter involves specialized medical knowledge. The critical question becomes what foundation a physician must lay to demonstrate competence to testify about specialized medical practices distinct from their own area of practice.

Medical specialization has become increasingly granular in modern practice, with subspecialties emerging within traditional medical specialties. Endocrinology represents one such specialized field within internal medicine, and testosterone replacement therapy constitutes a specific treatment modality within endocrinology requiring particularized knowledge. When a pathologist offers opinions regarding endocrinological standards of care without establishing any foundation for such expertise, the reliability of that testimony becomes questionable. New York courts have recognized that as medical practice becomes more specialized, the foundation requirements for expert testimony must account for this increased specialization.

Case Background

In Lavi v NYU Hospitals Center, the plaintiff brought a medical malpractice action against the defendants arising from alleged improper administration of testosterone replacement therapy. The defendants moved for summary judgment, submitting expert affidavits from physicians specializing in endocrinology who opined that the care provided met applicable standards. The plaintiffs opposed the motion with an affidavit from their own expert, a physician who specialized in pathology rather than endocrinology.

The pathology expert’s affidavit addressed the standards of care applicable to testosterone replacement therapy and opined that the defendants deviated from those standards. However, the affidavit did not indicate whether the expert had any specific training in endocrinology, had treated patients with testosterone replacement therapy, or had familiarized himself with the relevant medical literature on the subject. The trial court granted summary judgment to the defendants, and the plaintiffs appealed to the Second Department.

Jason Tenenbaum’s Analysis

Lavi v NYU Hosps. Ctr., 2015 NY Slip Op 08715 (2d Dept. 2015)

“In opposition, the plaintiffs failed to raise a triable issue of fact. The plaintiffs’ expert, who specialized in pathology, did not mention in his affidavit whether he had any specific training or expertise in endocrinology or particularized knowledge with regard to testosterone replacement therapy. Moreover, he did not indicate that he had familiarized himself with the relevant literature or otherwise set forth how he was, or became, familiar with the applicable standards of care in this specialized area of practice. ” While it is true that a medical expert need not be a specialist in a particular field in order to testify regarding accepted practices in that field … the witness nonetheless should be possessed of the requisite skill, training, education, knowledge or experience from which it can be assumed that the opinion rendered is reliable’”

“Thus, where a physician provides an opinion beyond his or her area of specialization, a foundation must be laid tending to support the reliability of the opinion rendered”

This is an area of law with so much variability. On one hand, we all agree that a physician can testify outside his specialization. On the other hand, the law limits a physician in offering testimony outside his or her specialty when the issue involves an area of specialized medicine. I think there needs to be a Court of Appeals case that sets forth a bright line rule, because I am losing track of what the proper statement of law is.

Legal Significance

The Second Department’s decision in Lavi reinforces the principle that cross-specialty expert testimony requires adequate foundational showing, while simultaneously acknowledging the flexibility that physicians may testify beyond their specialization. The court’s analysis recognizes that pathology and endocrinology represent sufficiently distinct specialties that expertise in one does not automatically confer competence to testify about the other without some demonstration of knowledge acquisition.

The decision’s emphasis on foundational requirements serves important gatekeeping functions in medical malpractice litigation. By requiring experts to articulate the basis for their competence in specialized areas, courts ensure that expert opinions rest on genuine expertise rather than credentials alone. The specific deficiencies identified by the court provide guidance for practitioners: experts testifying outside their specialty should indicate relevant training, clinical experience with the condition or treatment at issue, or at minimum, thorough familiarity with the current medical literature.

However, as Jason Tenenbaum’s analysis notes, the lack of a bright-line rule from the Court of Appeals creates uncertainty in practice. The case-by-case approach requires attorneys to make judgment calls about whether their expert’s qualifications will satisfy the court’s reliability inquiry. Some cases permit cross-specialty testimony with minimal foundation, while others, like Lavi, require detailed demonstration of acquired expertise. This variability complicates both case preparation and motion practice.

Practical Implications

Plaintiffs’ attorneys selecting medical experts must carefully consider whether the expert’s specialty aligns with the alleged malpractice. When cross-specialty testimony is necessary, counsel must work with the expert to develop a detailed foundation demonstrating the expert’s knowledge of the specialized field. This foundation should be explicit in the expert’s affidavit and should include references to specific training, clinical experience, or literature review that supports the expert’s competence in the area.

Defense counsel should scrutinize opposing experts’ qualifications with particular attention to whether the expert has articulated any foundation for opinions outside their specialty. Where foundational deficiencies exist, a motion to preclude the expert’s testimony may be appropriate before trial, or at minimum, the issue should be preserved for summary judgment purposes as occurred in Lavi. Cross-examination of experts at deposition should specifically address the basis for their claimed expertise in specialized areas distinct from their practice.

Trial courts serving as gatekeepers for expert testimony must engage in particularized inquiry regarding cross-specialty experts’ qualifications rather than accepting medical credentials at face value. The reliability standard requires assessment of whether the specific expert possesses the specific knowledge necessary to offer the specific opinions proffered in the case.

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