Relevance is the tendency of a given item of evidence to disprove any issue in the case under adjudication. It also covers the tendency of particular piece evidence to make one of the issues of the case either more likely or less probable than it would be without the same.
Evidence that has no bearing on any of the issues is irrelevant and is liable to be excluded.
‘Relevant evidence’ is defined as follows under Rule 401 of the Federal Rules of Evidence:
"Relevant evidence" means evidence having any tendency to make the existence of any fact that is of consequence to the determination of the action more probable or less probable than it would be without the evidence.
Relevant evidence is usually admissible unless barred by the Constitution or an Act of the Congress or by the Federal Rules of Evidence or by the rules prescribed by the Supreme Court.
Relevant evidence may be excluded in case the same is likely to prejudice or confuse the jury. Relevant evidence is also liable to be excluded if that would cause confusion of the issues or mislead the jury. In spite of relevance unnecessary presentation of cumulative evidence, likely to result in sheer wastage of time, is shut out. For instance, the court can disallow repetitive testimony on the same point.
Social policy considerations also exclude relevant evidence for larger cause. Evidence on settlement offers that have failed or plea negotiations that have not been accepted is inadmissible since that would discourage parties from offering to settle or pleading guilty to charges, respectively.