Pennsylvania Rules of Evidence allow a party to confront a witness with that witness’s prior inconsistent statements.  The purpose of confronting a witness with a prior inconsistent statement is to attack that witness’s credibility.  Often times this is done when a witness has given statements to the police and preliminary hearing testimony which differs from the witness’s trial testimony.

At the conclusion of trial, the judge will instruct the jury that if the jury believes that a witness was false with regards to one aspect of his testimony, the jury may discredit the entire witness’ testimony.