Legal Memorandum: Opinion Evidence in NY

Issue: In New York, must opinion evidence be based on the record at trial?

“It is settled and unquestioned law that opinion evidence must be based on facts in the record or personally known to the witness.  However, the Court of Appeals has recognized two limited exceptions to this rule and held that an expert may rely on out‑of‑court material if it is of a kind accepted in the profession as reliable in forming a professional opinion or if it comes from a witness subject full cross‑examination,” Comizio v. Hale, 165 A.D.2d 823, 560 N.Y.S.2d 198, 199 (2^nd Dep’t 1990) (citing Hambsch v. New York City Tr. Auth., 63 N.Y.2d 723, 480 N.Y.S.2d 195 and People v. Sugden, 35 N.Y.2d 453, 363 N.Y.S.2d 923).

This well‑reasoned rule exists because “an expert’s opinion not based on facts is worthless because an expert’s opinion is only as sound as the facts upon which it is based,” Kracker v. Spartan Chemical Co., Inc., 183 A.D.2d 810, 585 N.Y.S.2d 216, 219 (2^nd Dep’t 1992) (citing People v. Jones, 73 N.Y.2d 427, 541 N.Y.S.2d 340).  See Comizio v. Hale, supra.  See also People v. Angelo, 88 N.Y.2d 217, 644 N.Y.S.2d 460, 461 (1996) (to meet the professional reliability exception, the out‑of‑court evidence must be established as reliable).

However, it is well established that “an expert witness may not guess or speculate.”  See Kracker v. Spartan Chemical Co., Inc., 183 A.D.2d 810, […]