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Legal Concepts

What Is a Common Issue in a Class Action?

A class action requires that group members’ claims share at least one substantial common question of law or fact. This shared question — called the common issue — is why it makes sense to resolve those claims together rather than individually. Without a genuine common issue, a class action cannot be certified or maintained.

Key points

Point 1
The common issue requirement comes from s33C(1)(c) of the Federal Court of Australia Act 1976.
Point 2
The issue must be substantial — not trivial or peripheral to the overall claims.
Point 3
Not every element of each claim needs to be common — individual issues are resolved separately later.
Point 4
A court can create subgroups when different groups of members share distinct common issues.
Point 5
The lead applicant’s lawyers must clearly identify and plead the common issues in the statement of claim.

Examples of common issues

Common issues can arise from:

  • Whether a defendant’s product was defective — a factual issue common to all purchasers
  • Whether a company’s disclosure was misleading — a legal question common to all investors who bought shares in the relevant period
  • Whether a superannuation fund charged excessive fees — common to all members of the same product
  • Whether a data breach breached APP 11 — common to all whose data was exposed in the same incident

Individual issues — resolved separately

After common issues are resolved at trial, individual issues (such as the amount of loss each group member suffered) are dealt with separately. This may happen through a subgroup trial, an individual claims assessment process, or as part of settlement distribution. Courts design this process to minimise cost and delay.

What happens if no common issue exists?

If a court finds that the claims do not share a genuine common issue — or that individual issues overwhelm the common elements — it may decertify the class action. This is rare but does occur. Affected group members would then need to pursue individual claims, or wait for restructured proceedings.