The rules of evidence are guidelines that determine how evidence should be handled. These guidelines take many things into consideration. For example, they may determine what evidence is admissible, when it is admissible, and who is entitled to present it.
There is no universal set of rules of evidence. In the United States, the federal government has a set of guidelines. Each state also generally has its own set of rules. A court may also have its own set of rules. This means that evidence may be handled differently in a criminal case than it is in a civil case within the same state.
A purpose for the rules of evidence usually is quite similar. They were put into place to regulate the portion of the trial process that pertains to evidence so that proceedings can be fair for all involved. These rules also can be used to assist the judge or jury. These parties are known as the triers of fact.
The role of the triers of fact in a case is to weigh the evidence to make a final determination. If there are not rules that outline what evidence can be presented at what time and by whom, the duties of these individuals could become laborious and complicated. The best interest of the parties may be affected and justice may not be served.
Four types of evidence generally are recognized in a case: real, demonstrative, testimonial, and documentary evidence. Some rules of evidence only have limited relevance. This means that either they only apply to certain types of evidence or they only apply in certain situations.
One of the primary issues that the rules commonly address is whether or not certain things are admissible. There are some items and statements that obviously may be inadmissible. In many cases, however, it is necessary to analyze the rules of evidence carefully. Three factors that commonly are used to determine admissibility are whether the potential evidence is material, relevant, and competent. These terms often are defined in the legal codes that outline them.
Rules of evidence deal with many issues involving witnesses. These can include things such as the character and conduct of a witness. The rules also may determine how witnesses are interrogated and cross-examined. Rules may empower the court to determine when excessive amounts of time are being used in the examination of a single witness.
Another issue that commonly is determined by rules of evidence is the circumstances surrounding the submission of documents. Many courts, for example, require original documents to be submitted unless certain exceptions apply. The rules also might determine how documents can be proved or disproved when the original or a copy is unavailable.