Case law is law that derives from court cases and is thus judge-made law in the form of judicial opinions. It is also known as "common law." This name for the system of law comes from old England where judges who applied the "common law" of the land, made up of customs and conventions, well before there was official statutory law. Common law, or case law, allows for rulings to be made on unique circumstances that statutes or regulations may not have fully accounted for.
Case law will set forth precedents, legal authority for deciding subsequent cases with identical or similar facts or issues of law. This doctrine of following precedents is known as stare decisis (Latin for "to stand by things decided"). As noted in the Overview section of this guide, case law can be mandatory or persuasive depending on the jurisdiction. Trial courts generally do not publish their rulings or decisions and thus will not be used as case law. Appellate and Supreme Courts must be relied on for opinions.
In addition to the final product of a case opinion, there are other court documents that are present during a case's duration that are often needed or sought after in legal research. Filings with the court such as pleadings, briefs, motions, etc. are recorded in a case's docket, the official log of all proceedings and filings in a case's history. A docket number will be assigned by the court after a case is filed and this operates as a tracking number. The docket also contains pertinent information such as the judge(s), parties, attorneys of record, summaries of documents filed, and the date of those filings. Court records will include all of these documents, but other materials generated during the case such as oral argument transcripts and audio, trial transcripts, or jury instructions.