Also known as:impeach by bias · impeached by bias · impeaching by bias · impeachment for bias · bias impeachment · witness bias impeachment
Written by attorneys · grounded in primary & secondary sources — see below
A method of attacking a witness's credibility by introducing evidence that the witness has a motive to favor or disfavor a party. The motive may arise from personal interest, hostility, relationship, or other circumstances that could influence the testimony.
Sources & Authorities
How it applies
Common Examples
2
Probation Status and Favor with Prosecutors
In Carl's federal bank fraud trial the prosecution called Malik, a teller on juvenile probation for misusing customer accounts. Defense counsel sought to cross-examine Malik about that probation to show he might shade his testimony to please prosecutors and avoid revocation. The court barred the questions. The Confrontation Clause required that the defense be allowed to pursue the bias inquiry because Malik was the key witness and the probation status supplied a concrete motive to curry favor.
Organizational Membership Revealing Hostility
Dawn Vessel sued Summit Ocean for cargo damage. Summit called longshoreman Terry who testified the containers were properly stowed. Dawn Vessel sought to cross-examine Terry about his membership in a group whose rules required members to give favorable accounts protecting shipping companies. The evidence was offered to show Terry had an institutional incentive to favor the defendant. The membership supplied a specific motive that could affect the reliability of his testimony.
Select any source to read its text and confirm it supports the definition.
Cases
Study Supplements
United States v. Abel469 U.S. 45 (1984)
Common questions
Frequently Asked
4
When may a criminal defendant cross-examine a prosecution witness about a juvenile adjudication or probation status?+
The Confrontation Clause requires that the defendant be permitted to pursue the inquiry when the evidence is necessary to show bias or otherwise attack credibility. Evidentiary rules protecting juvenile records yield when they prevent exposure of a motive to testify favorably for the prosecution.
Supporting sources
Does Rule 610 bar all evidence of religious activity when offered to show bias?+
No. The rule prohibits use of religious beliefs or opinions to attack general credibility. Evidence of concrete defendant-specific animus or organizational pressure remains admissible even when the underlying motivation has a religious origin, provided the inquiry focuses on conduct rather than the content of faith.
Supporting sources
May settlement communications be admitted to show a witness's bias?+
Yes. Rules governing compromise negotiations expressly permit use of such statements for purposes other than proving liability or amount, including to demonstrate bias or prejudice.
Supporting sources
Is evidence of liability insurance admissible when offered solely to show bias?+
Yes. The rule barring insurance evidence to prove negligence expressly allows its use to show a witness's bias, prejudice, or financial interest.
Supporting sources
469 U.S. 45 (1984)Evidence
…evidentiary availability of cross-examination for bias. One commentator, recognizing the omission of any express treatment of impeachment for bias, prejudice, or corruption, observes that the Rules “clearly contemplate the use of the above-mentioned grounds of impeachment.” E. Cleary, McCormick on Evidence §40, p. 85 (3d ed. 1984).…
EvidencePrivileges and other policy exclusions · Compromise and payment of medical expensesNEXTGENIntermediate