In
common law legal systems, a
precedent or
authority is a principle or rule established in a previous
legal case that is either binding on or persuasive for a
court or other
tribunal when deciding subsequent cases with similar issues or
facts. Common law legal systems place great value on deciding cases according to consistent principled rules so that similar facts will yield similar and predictable outcomes, and observance of precedent is the mechanism by which that goal is attained.
Black's Law Dictionary defines "precedent" as a "rule of law established for the first time by a court for a particular type of case and thereafter referred to in deciding similar cases." Common law precedent is a third kind of law, on equal footing with
statutory law (statutes and codes enacted by legislative bodies), and
Delegated legislation (in U.K. parlance) or
regulatory law (in U.S. parlance) (regulations promulgated by executive branch agencies).