Impeachment Methods :
1. Prior inconsistent statements: on some prior occasion witness made a material statement inconsistent with current testimony; cannot be used as affirmative evidence unless was under oath at prior formal proceeding; witness must be confronted or be able to respond at some point, timing flexible; exception to FRE: if witness is opposing party, don’t have to give him opportunity to explain or deny prior statement
2. Bias, interest, or motive to misrepresent: in court’s discretion as to whether witness must be confronted; may be proven with extrinsic evidence because bias is a critical issue
3. Sensory deficiencies: anything that could affect witness’s perception or memory; no confrontation required; extrinsic evidence allowed
4. Bad character for truthfulness: any witness subject to this impeachment method; extrinsic evidence allowed; only opinion and/or reputation evidence allowed
5. Criminal convictions:  conviction of any crime involving dishonesty or false statement may be used to impeach; other felony convictions in court’s discretion; conviction or release from prison within 10 years from trial date; no confrontation required; method of proof: ask witness or introduce conviction record; don’t have to confront if using record
6. Bad acts: that reflect poorly on character for truthfulness; bound by witness’s answer, no extrinsic evidence allowed; cannot ask about an arrest, just whether he did the act
7. Contradiction: to show witness lied or made a mistake to something in direct examination; extrinsic evidence not allowed if issue is collateral