What are the Rules of Evidence?

Definition of Evidence

In legal terms, evidence covers the burden of proof, admissibility, relevance, weight and sufficiency of what should be admitted into the record of a legal proceeding. Evidence -- crucial in both civil and criminal proceedings -- may include blood or hair samples, video surveillance recordings, or witness testimony. The Federal Rules of Evidence (PDF) govern the admissibility of evidence in federal trials, but state rules of evidence are largely modeled after the federal rules.

If evidence is procured illegally, such as during an unlawful police search, then that evidence (and any other evidence it leads to) may not be used at trial. Evidence that is deemed irrelevant or prejudicial to a case also may be deemed inadmissible. Additionally, evidence may be thrown out if the integrity of its handling ("chain of custody") is in doubt.

There are four general types of evidence:

1. Real evidence (tangible things, such as a weapon)
2. Demonstrative (a model of what likely happened at a given time and place)
3. Documentary (a letter, blog post, or other document)
4. Testimonial (witness testimony)

Terms to Know

• Circumstantial Evidence: Evidence that tends to prove a factual matter by proving other events or circumstances from which the occurrence of the matter can be reasonably inferred.
• Corroborating Evidence: Evidence that is independent of and different from but that supplements and strengthens evidence already presented as proof of a factual matter.
• Hearsay: A statement made out of court and not under oath which is offered as proof that what is stated is true (usually deemed inadmissible).
• Exclusionary Rule: A rule of evidence that excludes or suppresses evidence obtained in violation of a defendant's constitutional rights.

Practice Area Notes

If you are a defendant in either a criminal or civil trial, your attorney may challenge and/or try to suppress evidence presented by the other party. One of your attorney's most vital tasks is to find evidence that best supports your case.

The main difference between the use of evidence in criminal and civil cases is the burden of proof . For a guilty verdict in a criminal trial, the prosecution must prove guilt "beyond a reasonable doubt." But for a civil defendant to be found liable, the plaintiff generally need only prove culpability "by a preponderance of the evidence" (a lower threshold).

Related Practice Areas

• Criminal Law
• Personal Injury -- Plaintiff

If you have additional questions about the rules of evidence and its role in a legal proceeding, consider speaking with a criminal defense or personal injury lawyer in your area.