History
The Role of Precedent in Common Law Systems
Quick fact
In the English case Donoghue v Stevenson (1932), the House of Lords created the modern law of negligence by establishing a general duty of care—a precedent so powerful that it still shapes product liability and personal injury law across many countries today.
Why this is interesting
You probably follow rules every day—like stopping at a red light. But what if the rule itself was made by someone just like you, only earlier? In common law, that is exactly how judges create law: by following the decisions of judges who came before them.
Read the full explanation
Understanding The Role of Precedent in Common Law Systems
Imagine a court system as a pyramid. At the top sits the highest court; below it are intermediate and lower courts. When a higher court decides a case, its reasoning becomes a "precedent"—a rule that all lower courts must follow when facing similar facts. This is called stare decisis, Latin for "to stand by things decided." It creates consistency: two people in similar situations should get similar outcomes. For a precedent to apply, the key facts of the new case must be materially similar to the old one. Judges extract the essential principle—the ratio decidendi—from the earlier decision and apply it. Anything else said in passing is obiter dictum, which is persuasive but not binding. If a judge thinks the facts are sufficiently different, they can distinguish the case and avoid the precedent. This mechanism ensures that law is predictable yet flexible enough to adapt to new circumstances.
A deeper explanation
The underlying principle is that legal rules gain authority from being followed over time. Precedent works because of the court hierarchy: binding precedent flows downward. The highest court's decisions bind all lower courts; intermediate courts bind those below them but not courts at the same level. This hierarchy is what gives precedent its coercive force. The ratio decidendi is the essential rationale—the rule of law that the decision stands for. Lower courts must apply it, but they can interpret its scope. Higher courts may overrule a precedent if it is outdated or erroneous, but they do so rarely, respecting stability. This creates a dynamic system: law evolves incrementally as new cases refine old principles. Precedent also promotes fairness (like cases treated alike) and limits judicial arbitrariness. However, it is not absolute; judges use techniques like distinguishing and overruling to shape the law. Thus, precedent is both a constraint and a tool for legal development, making common law a living tapestry of judge-made rules.