On the morning of November 21, 2023, Plaintiff Marie Iddriss (“Plaintiff”) fell down a flight of stairs in a building located at 123 West 20th Street in Manhattan after she exited the elevator on the second floor. Hong Diep Realty Incorporated (“Hong Diep”) was the landlord of the building with contractual responsibility for repairs in common areas and Kids At Work (“KAW”) was a tenant of space on the second floor. Plaintiff claimed that Hong Diep and KAW are responsible in negligence for her injuries. In particular, she claimed that Defendants failed to maintain handrails on the stairs which could have broken, and thereby prevented, her fall.
Plaintiff expected to call Douglas W. Peden as an expert at trial. Peden is a registered architect. Hong Diep filed a motion to preclude Plaintiff from offering Peden’s testimony “about the mechanism of Plaintiff’s fall and whether a handrail would have prevented it.”
Architecture Expert Witness
Douglas W. Peden provides expert analysis of construction and construction material defects, walkway construction, vertical misalignments, maintenance and safety, identification and delineation of hazards in stairs, ramps, corridors, platforms and level changes both outdoors and inside buildings and other structures.
Among other things, he has training and experience in the analysis and testimony for failure analysis and towards the resolution of personal injury litigation involving trip and fall injuries and code compliance issues.
Discussion by the Court
According to Peden, the unprotected stair landing was unreasonably dangerous and that the failure to provide required handrails on the stair violated the standard of care and applicable building codes.
Hong Diep claimed that these opinions implicate issues of biomechanics and causation, outside of Peden’s expertise, are not supported by a reliable methodology, and would mislead the jury and therefore not be helpful to it.
Plaintiff admitted that Peden cannot offer evidence regarding “the force of Plaintiff’s fall, her body position at the time of her fall, or the impact the absence of handrails had on Plaintiff’s body or injuries.” Plaintiff further offered no evidence of Peden’s qualifications to opine on the mechanism of injury in this case.
Peden will be able to testify regarding the function of handrails along stairs in preventing people from falling off elevated surfaces, preventing people from falling over the edge of a landing, and providing a point of anchorage. Those opinions fall within Peden’s area of expertise. He can also testify that a handrail would provide a person who was falling off the second floor landing and into the stair case “with an opportunity to arrest her fall and injury.” That general testimony too falls within Peden’s expertise and is supported by a reliable methodology.
However, because he lacked the expertise to opine on what caused Plaintiff’s injury or what would have prevented it, and because he identified no methodology supporting such opinions, he may not testify regarding Plaintiff’s particular mechanism of injury.
Held
The Court granted Hong Diep’s motion to exclude the testimony of Douglas Peden.
Key Takeaway
The district court must ensure that an expert, whether basing testimony on professional studies or personal experience, employs in the courtroom the same level of intellectual rigor that characterizes the practice of experts in the relevant field.
Peden lacked the qualifications to opine on the mechanism of injury in this case and failed to identify any methodology supporting such opinions.
Case Details:
| Case Caption: | Iddriss V. Hong Diep Realty Incorporated |
| Docket Number: | 1:25cv2799 |
| Court Name: | United States District Court, New York Southern |
| Order Date: | February 17, 2026 |
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