California Legal Research

Use this as a guide to researching California law using any of these three tools: Legal encyclopedias/treatises, Annotated codes, or Case Digests.

The Digest Approach

It's usually most efficient to use this approach when you have located a West Topic and Key Number that relates to your legal topic OR when you've found an important case about your topic. However, you can also use this approach if you're just starting with a legal concept.

What is a digest?

A digest is a large compilation of case law summaries, which are initially categorized into fairly broad topics, then subcategorized again into much more specific topics. Digests are NOT cumulative – they only cover specific periods of time. For example, West's California Digest covers cases decided between 1850 and 1950. West's California Digest 2d covers cases published from 1950 to present.

Which digests do I use to research California law?

West's California Digest and West's California Digest 2d (KFC57 W41) cover both reported California state cases and federal cases decided within California from 1850 to present. 

What is the West Topic and Key Number system?

The West Topic and Key Number system is a classification system that West developed to organize case law. West's digest volumes are arranged in alphabetical order by broad topics, like "Constitutional Law" and "Contracts." Each topic is further broken down into smaller subtopics, each of which is assigned a key number. It helps to think of each key number as representing a very specific and discrete legal concept within a broader legal topic.

What does a topic and key number look like?

When you're using the print digests, topics are listed in bold capital letters. Key numbers are preceded by a key symbol. The topics are listed in alphabetical order on the spines of the digest volumes. When you find the volume that you need, open it and look for your topic and key number at the top corners of the volume's pages. Once you've found the right pages, make sure you've found the beginning of the key number by looking for the key symbol and your number within the volume's text, which signals the beginning of the case summaries for that particular key number.

What if I'm using Westlaw?

Westlaw assigns numbers to topics online, so you will need to use a number instead of a topic name in your Westlaw search queries. Additionally, the key symbol is replaced with the letter "k." Here's an example of what a West Topic and Key Number would look like on Westlaw:




In this example, "92" is the number assigned to the topic, "Constitutional Law." The "k" stands for the key symbol. Finally the actual key number is 90(3). 


NOTE: Because West is the creator of the West key number system, it is not used on Lexis. 


What if I don't have a topic and key number when I begin using the digests?


You can use the descriptive word index at the end of the digest volumes to find some topics and key numbers relevant to your topic. Think of some relevant search terms, then look them up in the index to determine which topics and key numbers West has assigned to that particular concept.


What if I just know the name of an important case about my research topic?


You can look up your case in the "Table of Cases" at the end of the West digest volumes to find out which topics and key numbers are associated with your case. To find additional cases, simply review each assigned topic and key number listed under your case.

Can I use the West digest system online?

Yes. Because the online version is updated much more frequently than the print digests, we recommend checking your West Topic and Key Number online to be sure that you've found the most recent cases that have been assigned to that number.


Follow these steps to browse the West Topic and Key Number system online and find California cases assigned to particular numbers:

  • Sign on to Westlaw, then click "Site Map" at the top of the Westlaw home page.
  • Next, click on the link for "Key Number Digest (Custom Digest)."
  • You'll see a listing of all of the West topics along with the numbers that have been assigned to them. Click on the "+" sign next to a promising topic to view all of the key numbers for that topic. 
  • When you find the topic and key number that you need, enter it into the search box at the bottom right of the screen labeled "Search Using a Specific Topic & Key Number."  
  • Remember that you'll need to use the number assigned to your topic in this search box. For example, if you were looking for cases about the admissibility of bribery evidence, you can see when you browse the listing of topics that the topic "Bribery" has been assigned a number in Westlaw:  63. 
  • If you click on the "+" sign next to "Bribery," you'll see that there is a key number for admissibility of bribery evidence, shown as "k10."   Therefore, to search for cases assigned to this topic and key number, you would enter the following in the "Search Using a Specific Topic & Key Number" box:



  • At the next search screen, you can choose the jurisdiction that you need. For example, if you wanted to find California cases that have been assigned to this topic and key number, you would choose California from the "State" pull-down menu, then click "Search" at the bottom of the page.

Can I browse the West Topic and Key Number system in print?


Yes. West's Analysis of American Law (KFC57 W41) is a soft-bound volume that is located at the end of all digest volumes. You can review a broad topic until you find the most relevant key numbers for your research problem. 


Does the West Topic and Key Number system change over time?


Yes. As the law evolves, West adds and deletes topics and key numbers. If you're trying to use a West Topic and Key Number that you found in an older case for research, you may have trouble finding it, particularly if you're using the print digests. The best way to update an old topic and key number is to use Westlaw:

  • Choose a database that will contain the older case in which you found the topic and key number. For example, if you found a useful topic and key number in an older California Supreme Court case, use the "CA-CS" database. In the "Terms and Connectors" search screen, enter the old topic and key number in quotations in the Westlaw topic and key number format explained above.
  • You'll pull up a list of cases that contain this old topic and key number. Click on a case, then use the "term" arrow at the bottom of the screen to move to the case headnote containing the old topic and key number. You'll see a notation like this:



(Formerly 24k3)


  • On the screen, your old topic and key number will be highlighted as a search term, and it will be immediately preceded by the word "formerly."  Above the old number, you'll see the headnote that contains the new topic and key number that West has assigned for this legal concept (in the example above, the new topic and key number that you want to use to find cases is "22k2").

Subject Guide