Why Trust This Analysis
This article is part of our ongoing experts coverage, with 80 published articles analyzing experts issues across New York State. Attorney Jason Tenenbaum brings 24+ years of hands-on experience to this analysis, drawing from his work on more than 1,000 appeals, over 100,000 no-fault cases, and recovery of over $100 million for clients throughout Nassau County, Suffolk County, Queens, Brooklyn, Manhattan, and the Bronx. For personalized legal advice about how these principles apply to your specific situation, contact our Long Island office at (516) 750-0595 for a free consultation.
Key Takeaways
- An expert’s opinion “must be based on facts in the record or personally known to the witness” (Hambsch v New York City Tr. Auth.) — without record support it has no probative force.
- In Pascocello v Jibone, the First Department upheld preclusion of an expert opinion built on photographs for which no foundation had been laid.
- Experts cannot be used as a back door to put unauthenticated photographs or documents before the jury.
- Lay the foundation for every exhibit your expert relies on before the expert takes the stand.
In New York personal injury litigation, expert testimony plays a crucial role in establishing causation, damages, and the standard of care. However, courts maintain strict rules about what evidence experts can rely upon when forming their opinions. The foundation requirement ensures that expert testimony is based on reliable, admissible evidence rather than speculation or improperly introduced materials.
This evidentiary principle becomes particularly important when experts attempt to base opinions on photographs, medical records, or other documentary evidence. Without proper foundation establishing the authenticity, accuracy, and relevance of such materials, courts will exclude expert opinions that rely on them. This requirement protects the integrity of the judicial process and ensures that juries receive reliable expert testimony.
The foundation requirement is especially critical in personal injury cases where biomechanical evidence or photographic evidence might be used to reconstruct accident scenarios or demonstrate injury mechanisms. Courts have consistently held that experts cannot simply rely on any materials without proper evidentiary support, as seen in cases involving foundation requirements.
The Decision
Jason Tenenbaum’s Analysis:
Pascocello v Jibone, 2018 NY Slip Op 03466 (1st Dept. 2018)
“An expert’s opinion “must be based on facts in the record or personally known to the witness” (Hambsch v New York City Tr. Auth., 63 NY2d 723, 725 ; see Roques v Noble, 73 AD3d 204, 206 ), and in the absence of such record support, an expert’s opinion is without probative force (see Diaz v New York Downtown Hosp., 99 NY2d 542, 544 ). Here, Supreme Court properly precluded Dr. Toosi from offering an opinion based on photographs for which no proper foundation had been established.
The Legal Framework: Hambsch, Roques, and Diaz
The rule applied in Pascocello is decades old and remarkably stable. The Court of Appeals in Hambsch v New York City Transit Authority fixed the baseline: an expert may opine only from facts in the record or facts personally known to the witness. Diaz v New York Downtown Hospital supplies the consequence — an opinion lacking that support is “without probative force,” meaning it cannot defeat summary judgment or sustain a verdict. Roques v Noble carried the principle into the Appellate Division’s everyday summary judgment practice.
Photographs sit at the intersection of these rules. A photograph generally comes into evidence through a witness with personal knowledge who testifies that it fairly and accurately depicts what it purports to show. When no such witness authenticates the image, the photograph is not “in the record” in any meaningful sense — and an expert who builds an opinion on it is opining on facts that exist nowhere in admissible form. That is precisely the maneuver the trial court stopped, and the First Department endorsed stopping, in Pascocello.
Why This Matters for Trial Lawyers
For plaintiffs’ attorneys, the decision is a reminder that the expert disclosure is only half the job. If the expert’s causation or damages opinion depends on photographs — vehicle damage photos, scene photos, injury photos — someone with personal knowledge has to authenticate them first. An expert cannot bootstrap the exhibits into evidence, and an opinion announced without its factual predicate may be precluded outright, with no second chance in front of the jury.
For defense counsel, Pascocello is a preclusion tool. Cross-checking each opinion in the expert disclosure against the actual trial record — what has been admitted, what the expert personally observed — frequently reveals opinions floating free of any foundation. A motion in limine framed around Hambsch and Diaz can strip those opinions before openings.
The same record-support logic drives summary judgment practice in threshold and causation disputes, where courts routinely disregard expert affirmations untethered to admissible proof — a dynamic familiar from pre-existing injury litigation in New York personal injury cases, where experts must engage the actual medical record rather than assume facts not established.
Practice Pointers
- Map every expert opinion to its evidentiary source before trial: record cite, personal observation, or properly admitted exhibit.
- Authenticate photographs through a percipient witness — the plaintiff, an investigating officer, a treating provider — before the expert references them.
- Move in limine early. Foundation objections raised mid-testimony invite curative attempts; a pretrial ruling locks the issue down.
- Remember the summary judgment corollary: an expert affirmation without record support has no probative force and will not raise (or defeat) a triable issue of fact.
Frequently Asked Questions
What must an expert opinion be based on in New York?
Under Hambsch v New York City Transit Authority, an expert’s opinion must rest on facts in the record or facts personally known to the witness. An opinion lacking that support has no probative force under Diaz v New York Downtown Hospital.
Can an expert testify about photographs that were never admitted into evidence?
No. As Pascocello v Jibone confirms, a court may preclude an expert from offering an opinion based on photographs for which no proper foundation was established. The photographs must be authenticated — typically by a witness with personal knowledge — before an expert may rely on them.
How do you lay a foundation for a photograph at trial?
A witness familiar with the scene or subject testifies that the photograph fairly and accurately represents what it depicts as of the relevant time. Once admitted, the photograph becomes record evidence an expert can permissibly rely on.
Related Resources
- Pre-Existing Injuries in New York Personal Injury Cases — the firm’s cluster hub on injury causation proof
- The firm’s Legal Encyclopedia
- Personal Injury practice page
- Foundation Requirements in Medical Malpractice Expert Testimony
- Expert opinion
- The expert opinion
Legal Context
Why This Matters for Your Case
New York law is among the most complex and nuanced in the country, with distinct procedural rules, substantive doctrines, and court systems that differ significantly from other jurisdictions. The Civil Practice Law and Rules (CPLR) governs every stage of civil litigation, from service of process through trial and appeal. The Appellate Division, Appellate Term, and Court of Appeals create a rich and ever-evolving body of case law that practitioners must follow.
Attorney Jason Tenenbaum has practiced across these areas for over 24 years, writing more than 1,000 appellate briefs and publishing over 2,353 legal articles that attorneys and clients rely on for guidance. The analysis in this article reflects real courtroom experience — from motion practice in Civil Court and Supreme Court to oral arguments before the Appellate Division — and a deep understanding of how New York courts actually apply the law in practice.
About This Topic
Expert Testimony in New York Litigation
Expert testimony is essential in most personal injury and no-fault cases — from medical experts establishing causation and damages to accident reconstructionists and economic experts calculating lost earnings. New York courts apply specific rules governing expert qualifications, the foundation for expert opinions, the use of medical journals and treatises, and the sufficiency of expert evidence on summary judgment. These articles analyze the legal standards for expert testimony and practical strategies for presenting and challenging expert evidence.
80 published articles in Experts
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Common Questions About This Topic
3 answers from the firm's New York personal-injury and employment-law practice. Click any question to expand.
What must an expert opinion be based on in New York?
Under *Hambsch v New York City Transit Authority*, an expert's opinion must rest on facts in the record or facts personally known to the witness. An opinion lacking that support has no probative force under *Diaz v New York Downtown Hospital*.
Can an expert testify about photographs that were never admitted into evidence?
No. As *Pascocello v Jibone* confirms, a court may preclude an expert from offering an opinion based on photographs for which no proper foundation was established. The photographs must be authenticated — typically by a witness with personal knowledge — before an expert may rely on them.
How do you lay a foundation for a photograph at trial?
A witness familiar with the scene or subject testifies that the photograph fairly and accurately represents what it depicts as of the relevant time. Once admitted, the photograph becomes record evidence an expert can permissibly rely on.
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About the Author
Jason Tenenbaum, Esq.
Jason Tenenbaum is the founding attorney of the Law Office of Jason Tenenbaum, P.C., headquartered at 326 Walt Whitman Road, Suite C, Huntington Station, New York 11746. With over 24 years of experience since founding the firm in 2002, Jason has written more than 1,000 appeals, handled over 100,000 no-fault insurance cases, and recovered over $100 million for clients across Long Island, Nassau County, Suffolk County, Queens, Brooklyn, Manhattan, the Bronx, and Staten Island. He is one of the few attorneys in the state who both writes his own appellate briefs and tries his own cases.
Jason is admitted to practice in New York, New Jersey, Florida, Texas, Georgia, and Michigan state courts, as well as multiple federal courts. His 2,353+ published legal articles analyzing New York case law, procedural developments, and litigation strategy make him one of the most prolific legal commentators in the state. He earned his Juris Doctor from Syracuse University College of Law.
Disclaimer: This article is published by the Law Office of Jason Tenenbaum, P.C. for informational and educational purposes only. It does not constitute legal advice, and no attorney-client relationship is formed by reading this content. The legal principles discussed may not apply to your specific situation, and the law may have changed since this article was last updated.
New York law varies by jurisdiction — court decisions in one Appellate Division department may not be followed in another, and local court rules in Nassau County Supreme Court differ from those in Suffolk County Supreme Court, Kings County Civil Court, or Queens County Supreme Court. The Appellate Division, Second Department (which covers Long Island, Brooklyn, Queens, and Staten Island) and the Appellate Term (which hears appeals from lower courts) each have distinct procedural requirements and precedents that affect litigation strategy.
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