A court may criticize or even overrule an already-decided case, thus damaging or even destroying its precedential value. A court may also rule that a statute or regulation is void or invalid, meaning that it is in violation of another existing legal authority. In order to determine the precedential value of a legal authority, you need to Shepardize its citation. Attorneys are responsible for knowing the precedential value of any case, statute, or other legal authority before relying on it in an argument. Shepardizing shows you the precedential value of a legal authority, as well as helping to expand your research by leading you to new legal sources.
Most legal writing includes one or more citations.
A citation is a reference to a legal authority such as a case, statute, or regulation. A case, statute, regulation or other legal authority that has lost its precedential value. For example, a case may lose its precedential value by being reversed or overruled, or as the result of less drastic subsequent judicial treatment such as being criticized or questioned. First, it generally refers to a legal action litigated between two opposing parties, e.g., Ms. Smith and Mr. Jones. Following the outcome of the initial trial between Smith and Jones, the case may be heard by a court of appeals, and even eventually by the U.S. Supreme Court.