The cross-examination of witnesses is one of the safeguards to ensure accuracy and truthfulness.  The test of cross-examination is the best and most indispensable way known to the law for discovery of truth[i].

The right of an accused to cross-examine the witnesses against him/her is embodied in the confrontation clause of the U.S. Constitution amendment VI[ii].

When a witness has been examined in chief, the other party has the right to cross-examine for the purpose of ascertaining and exhibiting the situation of the witness with respect to the parties and to the subject of the litigation, his/her interest, his/her motive, his/her inclinations, his/her prejudices, his/her means of obtaining a correct and certain knowledge of the facts to which s/he has borne testimony, the manner in which s/he has used those means, and his/her powers of discernment, memory, and description.

A witness may be asked any question which reasonably tends to explain, contradict, or discredit his/her testimony.  While cross-examination of a witness ordinarily should be confined to matters as to which a witness has been examined in chief, s/he may be asked any question which reasonably tends to explain, contradict, or discredit his/her testimony[iii].

Opposing counsel is free to cross-examine an expert witness and challenge the strength of his/her testimony[iv].  This includes the ability of opposing counsel to question an expert on the standards that he or she reviewed before forming an opinion.

The purpose of cross-examination is to test the credibility of the witness and the accuracy and reasonableness of his/her direct testimony[v].

The cross-examination is a test to the truthfulness of the witness, to sift, modify, or explain what has been said, to develop new or old facts in a view favorable to the cross-examiner, or to discredit the witness, and, if s/he is the plaintiff, to test his/her good faith, the righteousness of his/her case[vi].

In a judicial investigation, the right of cross-examination is absolute and not a mere privilege of the one against whom a witness may be called[vii].  In a civil action, a party has the right to cross-examine witnesses against him/her whether the evidence is given ore tenus or by deposition.

The right of cross-examination is not without limits.  Trial judges retain wide latitude insofar as the Confrontation Clause[viii] is concerned to impose reasonable limits on cross-examination based on concerns about, among other things, harassment, prejudice, confusion of the issues, the witness’ safety, or interrogation that is repetitive or only marginally relevant[ix].

The discretion vested in trial courts to control the extent of cross-examination by which credibility of a witness is attacked does not extend to the entire exclusion of such testimony.

Although the extent to which cross-examination may go upon an appropriate subject is within the wide latitude of the trial court’s discretion, abuse of discretion which results in prejudice to the complaining party provides grounds for appellate action[x].

This is particularly true where collateral matters (issues not involved in the litigation) and a discrediting cross-examination[xi].  A cross-examination on prejudicial immaterial matter may require the granting of a new trial.  Immaterial and incompetent evidence may not  go before the jury under the guise that it impeaches or discredits the witness.

Thus it is the general rule that refusal to allow any cross-examination upon matters tending to affect the credibility of a witness is error.  Cross-examination of a witness for purpose of eliciting facts to show bias, prejudice, or friendship always is considered competent.

[i] Davis v. Arkansas Best Freight System, Inc., 239 Ark. 632, 634-635 (Ark. 1965).

[ii] United States v. Harris, 501 F.2d 1 (9th Cir. Cal. 1974).

[iii] Frierson V. Hines, 1967 OK 60 (Okla. 1967).

[iv] Heinz v. Heinz, 653 N.W.2d 334 (Iowa 2002).

[v] Floyd v. Fruit Industries, Inc., 144 Conn. 659 (Conn. 1957).

[vi] Frierson V. Hines, 1967 OK 60 (Okla. 1967).

[vii] Davis v. Arkansas Best Freight System, Inc., 239 Ark. 632, 634-635 (Ark. 1965).

[viii] USCS Const. Amend. 6.

[ix] United States v. Carty, 993 F.2d 1005 (1st Cir. R.I. 1993).

[x] Frierson V. Hines, 1967 OK 60 (Okla. 1967).

[xi] Hungate v. Hudson, 353 Mo. 944 (Mo. 1945).