Canada's legal system is based on a combination of common law and civil law traditions, passed down from the English and French systems.
In the common law tradition, law emerges from two sources:
In a common law system, judges must follow prior decisions from specific courts as determined by the hierarchy of the courts. So in order to research case law, you must understand Canada's court system.
The Civil Law Tradition in Canada
Most of Canada follows the common law tradition; however, Quebec follows the civil law tradition. In general, civil law jurisdictions do not place the same level of authority on case law and decisions are not considered binding. The highest authority is the Code (a comprehensive statement of rules meant to deal with any dispute), followed by doctrine (a body of academic commentary written by experts). For more information on the nuances of jurisprudence in Quebec, see Researching Quebec Law (2015) by Clare Mauro.
The hierarchy of the courts is an important aspect of the judicial system that allows decisions made by a lower court to be appealed (reviewed) by a higher court.
The judicial system is based on the concept of precedent—that cases with similar facts should be decided in a similar way. This means that judges follow the doctrine of stare decisis ("let the decision stand"), which requires them to follow the historical rulings of other judges who are higher in the judicial hierarchy of the same jurisdiction.
For example, a Supreme Court of Canada decision is binding on every other court below it (it must be followed). Conversely, a decision by the Ontario Court of Appeal is binding on the Ontario Superior Court, but is only persuasive to the Supreme Court of British Columbia because these courts are in different jurisdictions.
The following image provides an overview of the hierarchy of the courts (text-based version follows the image).
The court system can be grouped into the following 5 categories.
The court where a case originated in the system is called the court of first instance.
Cases can move through the court system on appeal. When a party is unsatisfied with a decision released from a court, they can file for leave (permission) to appeal to a higher court.
Leave to appeal is not automatically granted. The appeal court will review the file that appellants have submitted to determine if an appeal is justified. If allowed, the court will review the legal arguments from the trial-level court and the judge(s)'s decision and either affirm the lower court's decision or reverse it in full or in part. The decision of the appeal court will then take precedence over the decision of the trial court.
Since a decision from any court can be overturned on appeal, you must always look at a case's subsequent history to see if it stands as "good law" before relying on it in your legal research.
►See Noting Up Case Law for information on how to do so.