10 What Is Case Law?
Kate Thompson
Learning Outcomes
After reading this chapter you will be able to:
- recognise the elements of a case;
- understand how cases are published and the difference between a reported and an unreported case;
- identify components of a case citation and what the abbreviations mean;
- find a case when you have a citation;
- find a case on a topic or issue.
A case, often referred to as a decision or judgment, is a written record of a judge’s or judges’ reasoning or decision-making applied to a particular dispute. When deciding cases, judges apply legislation or common law, and apply the doctrine of precedent (stare decisis), which means the court must follow the decisions reached by a higher court in the same jurisdiction.[1] For this reason, case law has precedential value and is sometimes known as common law or judge-made law.
Case law is a primary source of law in Aotearoa New Zealand.
Anatomy of a Case
Understanding the different parts of a case is helpful for case-law research. The figure below shows some of the key parts of a case.
- citation;
- party names;
- court;
- judge or judges;
- hearing date or dates.
Headnote
The headnote of the decision contains catchwords and a summary of the case. Catchwords are keywords and phrases, separated by dashes, summarising the legal principles and legislation discussed in the case. The summary provides a short description of the matter and outlines the key findings of the case.
The headnote and its keywords are not officially part of the judgment. The headnote is written by a law reporter, who is an employee of the publisher, not by a judge. Accordingly, do not quote from it.
Judgment
The start of the judgment proper is usually indicated by the judge’s surname (eg Cooper J). If the judgment is from an appellate court (eg the Court of Appeal or Supreme Court) with several judges sitting, there may be multiple judgments. This is certainly the situation if one of the judges does not agree with the others and writes a dissenting judgment.[2]
Each judgment will generally include:
- the litigation history of the case;
- statement of facts;
- relevant legal issues, legal principles and application to the case;
- conclusion;
- order of the court.
Learning how to analyse a case and distinguish the ratio decidendi[3] is a core skill in legal studies.
- Peter Spiller Dictionary of New Zealand Law (eBook ed, LexisNexis, 2019–). ↵
- See Vector Gas Ltd v Bay of Plenty Energy Ltd [2010] NZSC 5, [2010] 2 NZLR 444 for a classic example of a dissenting judgment. ↵
- Latin, reason for deciding. The principle of law on which a court bases its decision. The ratio decidendi of a case is binding on inferior courts under the system of judicial precedent. Peter Spiller Dictionary of New Zealand Law (eBook ed, LexisNexis, 2019–). ↵
