Prior consistent statements and prior inconsistent statements

In the law of evidence, a prior inconsistent statement is when a witness, testifying at trial, makes a statement that is inconsistent with a previous statement given at an earlier time such as during a discovery, interview, or interrogation. The examiner can impeach the witness when such a statement is found.

Before the witness can be impeached the examiner must have extrinsic evidence of the prior statement and they must provide the witness with the opportunity to adopt or reject the previous statement.

The opposite concept is the prior consistent statement. A prior consistent statement may be introduced to bolster a witness in response to any attack on the credibility of that witness, including a prior inconsistent statement. A prior consistent statement can not be introduced into evidence unless and until the credibility of the witness has been attacked.

One form of prior consistent statement is excepted from this rule, that of prior identification by the witness of another person in a lineup.