Impeachment of a witness other than defendant by prior conviction is a legal process in which a witness’s credibility is called into question due to a prior criminal conviction. It is a form of evidentiary attack on the witness’s testimony, and can be used to discredit the witness in the eyes of the jury. There are two types of impeachment of a witness other than defendant by prior conviction: direct impeachment and collateral impeachment. Direct impeachment is the process in which the defense attorney presents evidence that the witness has a prior criminal conviction, with the purpose of discrediting the witness. This type of impeachment must be done within the scope of the rules of evidence and the judge must determine if the prior conviction is relevant to the case. Collateral impeachment occurs when the defense attorney brings up evidence of the witness’s prior criminal convictions in order to prove that the witness is untrustworthy and thus, not to be believed. This type of impeachment does not need to be done within the scope of the rules of evidence, and it does not need to be approved by the judge.