What does “compulsory joinder” refer to in legal terms?

Compulsory joinder refers to the legal obligation to include certain parties in a lawsuit in order for the case to be properly adjudicated. This concept is grounded in the need to ensure that all interested parties are present so that their rights are protected and the court can issue a comprehensive resolution to the dispute. When a party is considered "necessary" under the rules of compulsory joinder, it means that their absence could impede the court's ability to provide complete relief or might expose existing parties to the risk of multiple or inconsistent obligations.

In contrast, the other choices either misrepresent the concept or introduce unrelated ideas. A voluntary approach suggests that parties can be joined at the discretion of the litigants rather than being mandatory, while dismissing unnecessary claims and discussing claims that arise independently do not pertain to the essence of compulsory joinder, which focuses specifically on the necessity of joining certain parties to avoid prejudice and ensure justice.