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West's Key Number System®
The key to finding good law

The logical organization of legal materials is essential to the maintenance of a legal system based on precedent. For more than 100 years, the bench and bar have relied on the Key Number System's organization of caselaw to locate that precedent.

Key Number System But what IS the Key Number System... and why do I need to know about it?
West's Key Number System is, simply put, the most comprehensive and widely used indexing system for caselaw materials. Understanding the Key Number System is an indispensable part of learning how to do effective legal research.

Which means?...
The Key Number System is something like a really big interactive outline that works like this: First, the American system of law is broken down into Major Topics -- there are more than 400, including things like Civil Rights, Pretrial Procedure, and Treaties. Each of those topics is divided, in greater and greater detail, into individual units that represent a specific legal concept -- like steps in an outline. Each of the lines (and there are more than 80,000 of them!) has a unique number that allows you to find it on the outline. This number is called a Key Number. The whole outline, along with the case headnotes classified to it, is called the Key Number System.

And this is important to me because... Why?
Because it makes legal research easier, more accurate, and more relevant. The Key Number System is an index you use to find opinions relevant to whatever legal problem you are working on AND it is a list of issues important in the law. This means that it will not only help you find the cases you want, but it will also help you identify the issues you need to consider in the first place!

Okay. I think I get the general idea. But that still doesn't explain how I'm going to find the case I need.
Let's back up for a moment, starting with the caselaw and working our way back to the Key Numbers. A court issues an opinion in a case. A copy of the case is obtained by West, where highly trained Attorney Editors read the cases and pick out the points of law addressed in the case. Written as a short, concise paragraph, these are called headnotes.

So, one point of law = one headnote. Then what?
Those headnotes are then passed along to attorney editors who are experts in figuring out where points of law belong in the huge Key Number System "outline." These "Classifiers" find the correct location on the outline, and assign a Key Number to the headnote. Here is the great part: all headnotes dealing with a particular point of law will have the same Key Number! Talk about a great research tool!!

All you have to do is know which Key Number describes the problem or point of law on which you would like to find caselaw. The rest has all been done for you!

Are you telling me that if I want to do good legal research that I'm going to have to memorize more than 80,000 Key Numbers?
No way!! That is the great thing about the way the Key Number System® has been put together. You don't really have to memorize anything. You just start with an idea and follow a logical thread of information until you find what you need. The Key Number System's organization does all the real work for you. All you need to do is become familiar with the concept of Key Numbers and how they work.

Sounds good. Where do I start?
A good place to start is figuring out how to find the right topic. The links below will help you with that and many other research issues. And make sure you check out the Headnote of the Week, too!


Find Key Number for Topic

Where Do I Find Key Numbers?

History of Key Number System

Explanation of Key Number Analysis

Guide to Electronic Research

Glossary of Terms

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