This month's column discusses two issues arising under New York law governing impeachment: first, the ban on the use of extrinsic evidence that contradicts the witness's testimony on a collateral matter; and second, impeachment of a hearsay declarant whose statement is admitted into evidence pursuant to a hearsay exception. These two issues were the subject of recent Appellate Division decisions which prompt this column.

Collateral Matters

New York's well-settled rule is that “a cross-examiner cannot contradict a witness's answers concerning collateral matters by producing extrinsic evidence for the sole purpose of impeaching credibility.”1 Extrinsic evidence refers to evidence other than as brought out on cross-examination of the witness, i.e., documents or testimony from other witnesses. Thus, if a matter is collateral, the cross-examiner may question the witness about it, but must take the witness's answer and is not free to put in other evidence to contradict the witness's answers.2

What is a “collateral” matter for purposes of this rule? The answer has been provided by the courts through stating what is not a collateral matter, namely, a matter is not collateral if it is relevant to the merits of the action or if it is independently admissible to impeach the witness.3 As to the latter, this would encompass the traditional impeachment categories of bias, interest, corrupting influences, prior inconsistent statements, competency impairments, “bad acts,” bad reputation for truthfulness and prior criminal convictions.4

The practical effect of this rule is that it prohibits the jury from fully considering that where the witness's testimony on a particular matter is false or erroneous (assuming the contradictory evidence is believed), other matters testified to by the witness may be false or erroneous as well.5 The rule, and this result, is justified by the “obvious and salutary purpose…to prevent needless multiplication of issues in a case so as to confuse the jury.”6

Bad Acts

One situation where this rule is applicable occurs when a witness is properly cross-examined with respect to a prior bad act the witness allegedly committed and the witness denies committing it. It was addressed by the Fourth Department's thoughtful decision in Young v. Lacy, 120 A.D.3d 1561 (2014). In Young, plaintiff sought to recover for her injuries sustained in a motor vehicle accident with defendant.