Case law is based upon precedent or authority. In order to find out if a case can be used as authority, check to see whether the case has been followed, distinguished, limited or questioned in subsequent court cases. This is done by "Shepardizing" – using Shepard's Citations to see how and when another court has cited the first decision. Shepardizing a case helps determine the precedential value of a legal authority. It is crucial to make sure the precedents are up-to-date.
Shepardizing a case helps determine the precedential value of a legal authority. Most commonly associated with case law, Shepard's citators are also published for the constitution and statutory law.
A legal citation for a case identifies the name of the court reporter in which the opinion is published and identifies the volume and page. In the Shepard's citator sources, the term "citation" is used more specifically to indicate a reference in a later authority to an earlier authority. The earlier authority is known as the "cited" case, statute, etc. and the later authorities are referred to as the "citing" case.