Evidence is the means by which parties attempt to prove or disprove the facts in issue in a proceeding. Evidentiary rulings are a critical part of trials, and in many instances determine the outcome. Errors and mistakes on issues of evidence have profound impacts, including wrongful convictions and perpetrators not being brought to justice. The central objective of the rules of evidence is to facilitate a reliable search for the truth. However, the rules of evidence also engage other objectives, such as protecting privacy rights, preserving certain societal relationships, and deterring state misconduct. The rules of evidence are largely based on determining:

 1.whether or not the evidence will assist the search for the truth; and,

2. the circumstances in which another value must take precedence over the search for the truth.