Case law is the collection of past legal decisions written by courts and similar tribunals in the course of deciding cases, in which the law was analyzed using these cases to resolve ambiguities for deciding current cases. These past decisions are called "case law", or precedent. Stare decisis—a Latin phrase meaning “let the decision stand”—is the principle by which judges are bound to such past decisions. These judicial interpretations are distinguished from statutory law, which are codes enacted by legislative bodies, and regulatory law, which are established by executive agencies based on statutes. In some jurisdictions, case law can be applied to ongoing adjudication; for example, criminal proceedings or family law.
The different roles of case law in civil and common law traditions create differences in the way that courts render decisions. Common law courts generally explain in detail the legal rationale behind their decisions, with citations of both legislation and previous relevant judgments, and often interpret the wider legal principles. The necessary analysis (called ratio decidendi), then constitutes a precedent binding on other courts; further analyses not strictly necessary to the determination of the current case are called obiter dicta, which constitute persuasive authority but are not technically binding. By contrast, decisions in civil law jurisdictions are generally shorter, referring only to statutes. The reason for this difference is that these civil law jurisdictions adhere to a tradition that the reader should be able to deduce the logic from the decision and the statutes.
In federal or multi-jurisdictional law systems there may exist conflicts between the various lower appellate courts. Sometimes these differences may not be resolved, and it may be necessary to distinguish how the law is applied in one district, province, division or appellate department. Usually, only an appeal accepted by the court of last resort will resolve such differences and, for many reasons, such appeals are often not granted.
Any court may seek to distinguish the present case from that of a binding precedent, to reach a different conclusion. The validity of such a distinction may or may not be accepted on appeal of that judgment to a higher court. An appellate court may also decide on an entirely new and different analysis from that of junior courts, and may or may not be bound by its own previous decisions, or in any case, may distinguish them on the facts.
Where there are several members of a court deciding a case, there may be one or more judgments given (or reported). Only the reason for the decision of the majority can constitute a binding precedent, but all may be cited as persuasive, or their reasoning may be adopted in an argument. Apart from the rules of procedure for precedent, the weight given to any reported judgment may depend on the reputation of both the reporter and the judges.