What is the purpose of the Key Number in West’s indexing system?

• A. It identifies the author of the case.
• B. It serves as a permanent number for a specific point of law.
• C. It indicates the appellate court’s ruling date.
• D. It lists all cases in a topic.

Answer: (B)

Key Numbers are permanent identifiers assigned to a specific point of law within West’s Digest system, used to categorize and retrieve case law by issue. They stay the same across different cases and jurisdictions, so researchers can jump to all decisions that address the same legal concept by following that number. This makes it easy to build a complete picture of how a particular point of law has been treated over time and across courts.

So the best choice is that the Key Number serves as a permanent number for a specific point of law. It isn’t about who wrote a case, nor about the ruling date, and it doesn’t simply list every case in a topic—it's a stable analytical tag that groups all relevant authorities under one issue.