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March 17, 2026

Third Department Takes a Strict Stance on Expert Disclosure Rule

The Appellate Division, Third Department, has mandated strict compliance with expert disclosure rules, whereas other New York State appellate courts have found that the same rules did not apply. The court’s decision in Dewan-Zemko et al. v. Hunter Mountain Ski Bowl, Inc.1 reveals a more exacting approach to the New York Civil Practice Law and Rules (CPLR) 3101 compared to other courts in New York State. 

In Dewan-Zemko, the plaintiff wanted her treating doctor to testify as an expert regarding the cause of her injuries. She disclosed her treating physician to the defendant later than the local judicial district rules permitted, however. The defendant objected, arguing that the late notice violated the local rule and CPLR as well as the Third Department’s well-established precedent that all expert medical witnesses, including treating physicians and nurses, must be disclosed timely. The trial court granted the defendant’s motion to preclude the expert from testifying at trial. 

The Third Department sided with the defendant, affirming the trial court’s order, noting the plaintiff’s failure to comply with the defendant’s demands and prior court orders directing expert disclosure. The Third Department acknowledged that its rule is inconsistent with the other appellate departments in New York State, where failure to serve a formal disclosure of a treating physician will not result in preclusion if the physician’s records and reports have already been produced during discovery. The Third Department explained: “it is not opposing counsel’s responsibility to cull through copious medical records to ferret out the qualifications of the subject expert, the facts or opinions that will form the basis for his or her testimony at trial, and/or the ground upon which the resulting opinion will be based.”2

This decision serves as a reminder for anyone involved in a lawsuit in the Third Department to carefully follow the rules related to disclosing expert witnesses. Failure to do so could mean losing the opportunity to have important testimony heard in court. For cases venued in the Third Department, it is crucial to work closely with legal counsel to ensure all expert witnesses, including treating physicians and nurses, are disclosed on time and in compliance with the CPLR.  

If you have any questions regarding the content of this alert, please contact Matthew Smith, associate, at msmith@barclaydamon.com; Matthew Larkin, Torts & Products Liability Defense Practice Area chair, at mlarkin@barclaydamon.com; or another member of the firm’s Torts & Products Liability Defense Practice Area.
                                                                                                

12026 NY Slip Op 00413.
2Citing Colucci v. Stuyvesant Plaza, Inc., 157 A.D.3d 1095, 1100 (3d Dep’t 2018).
 

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