Precedent

A precedent is a court decision that serves as an authority for deciding later cases involving similar facts or legal questions. In Canada's common law system, precedent is the primary way judge-made law develops: each decision adds to the body of law that future courts consult.

The force of a precedent depends on which court decided it. Under the doctrine of stare decisis, decisions of higher courts in the same jurisdiction are binding authority on lower courts, while decisions from other provinces or from courts at the same level are persuasive authority. Only the ratio decidendi of a case (its essential legal reasoning) binds later courts; obiter dicta do not.

In legal research, finding the leading precedent on an issue and confirming it is still good law (by noting it up) is a core task. A single Supreme Court of Canada precedent can settle a question for every court in the country.