Skip to content Skip to navigation menu
Your browser is not supported by this site.
Please update to the latest version, or use a different browser for the best experience.

Using the West Key Number System

Silvia Fejka
Reference Attorney, Thomson Reuters

Every legal researcher’s goal is to find the best way to zero in on a particular legal issue and quickly find on-point cases. However, with all of the information available on the internet, is it really possible to find the exact case that you need quickly? Even if you are able to find a relevant case quickly, can you feel confident that there isn’t another case out there that is a better fit? Surprisingly, the answer to both of these questions is yes.

ABOUT the Key Number System

The Key Number System was the first of its kind when created by West Publishing more than 100 years ago. A master classification system of U.S. law, the Key Number System allows our Attorney Editors to organize cases by corresponding legal issues and topics. Our Key Number Digest books help legal researchers quickly and efficiently find relevant case law among the stacks and shelves in vast law libraries. Few analog tools have made the transition to our digital world better than Key Numbers, and using Key Numbers on Westlaw can make quick work of complicated legal research tasks. Use any of the methods below to take advantage of West’s Key Number System, integrated with KeyCite and always up to date.

BROWSE comprehensive Key Numbers to pinpoint legal concepts

The first step in utilizing the Key Number System is finding an applicable Key Number. The Westlaw homepage link to “Key Numbers” allows you to browse to level of specificity by topic. Alternatively, a link appears under the “Looking for This?” autosuggestion when you start to type Key Numbers in the search bar at the top of the screen.

By clicking these links, you are brought to the West Key Number System content page. Narrowing by topic will ultimately take you to a list of headnotes, the equivalent of a particular Key Number Digest in print. From here, you can run a search or narrow by jurisdiction as needed.

If you navigate back to the main Key Number page, you can see two options: search headnotes or Key Numbers and topics. The main search bar at the top of the screen will search across all of the headnotes within the Key Number System. This is helpful to find headnotes related to your issue and then see where they are classified within the Key Number System. The second search bar in the gray box searches only Key Numbers and topics. This option helps to find specific Key Numbers that use the language you have, whereas the search in headnotes provides a broader option to find helpful headnotes or related Key Numbers.

LOCATE cases discussing similar legal concepts and principles

Finding one case on point will directly lead you to others through Key Numbers. Headnotes are summaries of specific points of law addressed in a particular case, drafted by Westlaw Attorney Editors to ensure that topics include relevant cases even where those cases may use atypical language. Applicable headnotes are always listed at the top of a case, and so provide a good alternative entry point into the Key Number System. After reviewing cases and locating a helpful headnote, click into the Key Number System through the classification hierarchy next to the headnote. (You may need to click “Change View” above the first headnote.)

After choosing a Key Number, you can search within using the box along the left, or you may look in a different jurisdiction by using the Change link under the Key Number heading at the top of the page.

SEARCH Key Numbers using comprehensive WestSearch

Finally, you can search Key Numbers across all Westlaw content by running a plain language search from the global search box on the homepage. You will see a link to Key Numbers in the gray bar along the left after running a search. For additional Westlaw tips, visit our training and support page.

Not a Westlaw subscriber? Sign-up for a free trial today.

About the author

Silvia Fejka

Silvia is a Reference Attorney for Thomson Reuters, helping customers daily with formulating search queries and utilizing Westlaw. She has previous experience as a municipal attorney and is barred in both Colorado and Maryland.