Case law research identifies court opinions that are relevant to a dispute, according to the University of Washington Law Library. The most relevant court opinions are those that are factually similar to the dispute and involve the same question of law, states The Judicial Branch of California.
Case law is the law of the judicial branch of government, explains the Georgia State University Law Library. State and federal courts both issue case law. The federal court system and each state's court system generally include district courts, which try cases, appellate courts, and a supreme court.
In the United States, opinions that courts issue are binding on those courts and the courts below them in a process known as stare decisis, observes the Georgia State University Law Library. Accordingly, in order to understand how a court should decide a dispute, researchers must find each opinion written by that court and the courts above it. In some situations, federal case law is binding in state courts, and state case law is binding in federal court. As a result, researchers must often search the opinions of several courts, both at the state and federal level.
Researchers rely on several sources to find case law, notes the Georgia State University Law Library. These include annotated statutes, digests that compile opinions by topic, legal encyclopedias, and electronic databases such as LexisNexis Academic. To search these resources, researchers need to have in mind legal topics or keywords related to the dispute.