Impeachment of Witness — Prior Bad Acts (F.R.E. 608(b)) is a type of evidence used in litigation in the United States. It is a rule of evidence that allows a party to a case to impeach the credibility of a witness by introducing evidence that the witness has engaged in prior bad acts. This is limited to acts that are probative of truthfulness or untruthfulness, and the evidence must be relevant to the case. The Federal Rules of Evidence 608(b) governs the impeachment of a witness by evidence of prior bad acts. There are two types of Impeachment of Witness — Prior Bad Acts (F.R.E. 608(b)). The first type is direct impeachment, which is when the evidence of the prior bad act is directly related to the witness’s credibility. The second type is collateral impeachment, which is when the evidence of the prior bad act is not related to the witness’s credibility but is used to show that the witness’s testimony is not reliable.