What is cross-examination at an Ontario civil trial?

Cross-examination is the questioning of a witness by the party who did not call them. At an Ontario civil trial, once a witness gives their evidence in chief (direct examination by the party who called them), the opposing party's lawyer has the right to cross-examine that witness. Cross-examination is one of the most important tools for testing the reliability and credibility of evidence.

Unlike examination in chief — where the questioner generally cannot lead the witness to a specific answer — cross-examination allows leading questions. The cross-examiner can directly suggest facts and ask the witness to confirm or deny them. Cross-examination can explore inconsistencies between the witness's trial testimony and what they said in prior statements (including their discovery evidence), challenge the witness's perception or memory, suggest bias or motive, and confront the witness with contradictory evidence.

The goal of cross-examination varies depending on the case. Sometimes the objective is to destroy the witness's credibility entirely; other times it is to extract useful admissions that support the cross-examiner's case while limiting the damage done by the evidence in chief. Effective cross-examination requires careful preparation — a lawyer who knows the record thoroughly can use prior inconsistent statements, discovery answers, and documentary evidence to challenge what a witness said on the stand. Poor cross-examination can sometimes strengthen unfavorable testimony.