Opinion evidence must be based on facts in the record. An expert cannot speculate, guess, or reach a conclusion by assuming material facts not supported by the evidence. The opinion must be supported either by facts disclosed by the evidence or by facts known to the expert personally. It is essential that the facts upon which the opinion is based be established, or fairly inferable, from the evidence.
An expert's affirmation that sets forth general conclusions, misstatements of evidence, and unsupported assertions, and which fails to address the opinions of defendant's expert, is insufficient to defeat summary judgment. Also insufficient is is one which raises for the first time in opposition to summary judgment a new theory of liability that has not been set forth in the bills of particulars or in the complaint.
Cabrera v. Golden, NY Slip Op 04112 (1st Dep't August 1, 2024)
