By Eugene Boggs, eHow Contributor
A trial's goal is to determine, as far as possible, the truth about a matter in dispute. Accordingly, evidence (information offered to prove or disprove issues essential to the dispute's outcome) must be reliable (have a strong likelihood of being truthful) to warrant admission (consideration by the fact-finder, i.e., either a jury or a judge). The law of evidence sets out rules of admissibility (reliability assessment) of various classes of information.

    Features

  1. The law of evidence in the United States is both statutory (the product of legislation) and common law (the product of court decisions). There is a body of evidence law for federal courts and others for each state court system within the United States. While many traditional rules are common to virtually all jurisdictions, there are others among the 50 states that address specific regional preferences and cultural traditions. So, any discussion of "the law of evidence" as brief as this one is, emphatically, a mere survey of the topic.

    Significance

  2. Without the gatekeeper role of the rules of evidence, trials would likely be little more than exchanges of insults, rumors, slanders and outright lies, the proverbial "witch hunt." (See, for a dramatic example, "The Crucible," Arthur Miller's play about the witch trials in Salem, Massachusetts, in 1692.) Notwithstanding the inevitable lapses, the rules of evidence significantly limit the nature and extent of evidentiary abuse. The rules also flag some admitted evidence as possibly doubtful (the so-called "weighing" of the evidence).

    Function

  3. Besides serving as reliability assessors, rules of evidence advance other public policy goals such as recognizing the sanctity of certain confidential relationships. Privileges (various "you-don't-have-to-testify" rules) allow certain people in confidential relationships (typically spouses, doctor and patient, religious leader and follower, etc.) to maintain their confidences in the face of efforts to have them divulge that information at a trial.

    Types

  4. There are four main categories of evidence:

    Real: "Real" items of evidence are things; for example, a gun allegedly used in a robbery.

    Testimonial: A person tells under oath what he or she knows about the matter being tried.

    Demonstrative: Common examples are maps, graphs, plaster casts of tire tracks. They customarily illustrate and corroborate testimonial evidence.

    Documentary: Documents (writings) are, of course, things, and hence a form of real evidence, but their consideration warrants its own category when the document is offered not simply as a piece of paper, but to claim that what is written on the paper is true.

    Misconceptions

  5. "He said, she said." This type of case cannot be tried because it is one person's word against another's. Not true. While both persons' testimony may be admitted into evidence, a jury (or judge hearing the case without a jury) may, based on the testimony alone, or that and other evidence presented, believe one and not the other.