Impeachment by prior inconsistent statement not under oath is a method of attacking a witness's credibility in court. This type of impeachment is used when a witness has made a statement that is inconsistent with their testimony on the stand. The statement must be made outside of court, and must not have been made under oath. Examples of statements that can be used for impeachment include written statements, oral statements, and statements made in prior legal proceedings. There are two types of impeachment by prior inconsistent statement not under oath: extrinsic and intrinsic. Extrinsic impeachment involves introducing evidence of the witness's prior inconsistent statement in order to impeach them. Intrinsic impeachment involves the attorney questioning the witness about their prior inconsistent statement during cross-examination in order to impeach them.