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Case Law Research: Methods of Finding Cases

A guide designed for first year law students on the MU Law Library's resources for case law research.

Finding Cases Using Headnotes

You may hear this referred to as a "case in hand" or "one good case" searching method. What this refers to is using an on point case that you have already found to find other relevant cases on your issue by using that case's headnotes. 

Headnotes: Headnotes are very short entries on legal issues that are found at the beginning of a case. From a headnote you can click on a West Key Number, or a  Lexis Topic Document or Topic Index link to find additional cases.

  • Westlaw: After finding an on point case, read the headnotes and find the one most relevant to your issue. Click on a topic or key number link to see a list of all cases that fall under the same topic and key number. You can refine your search by choosing a different jurisdiction at the top of the page.
  • Lexis Advance: After finding a case you like, read through the Lexis Headnotes at the beginning of the case, and find the one(s) most relevant to your issue. Look at the listing of topics and sub-topics above your headnote and choose the one of most interest to you. From here you have a couple of options.
    • Topic Document - this is similar to looking at a digest document in WestlawNext; you will first be shown a list of cases under this topic, which you can narrow by jurisdiction or by searching within results; but you can also look at other types of legal materials that fall under this topic by selecting them from the tabs at the top.
    • Topic Index - this is similar to browsing the West Key Number System; you are presented with an expandable tree of legal topics, which you can search in the provided search bar at the top of the tab or browse.

Finding Cases Using Annotated Statutes

Annotated statutes contain references to other materials related to that particular statute, including case annotations. Case annotations are editorially selected summaries of cases that are illustrative of how a particular statute has been applied by the courts.

Finding Case Annotations

  • WestlawNext - In Westlaw case annotations are called Notes of Decisions. They are available in three different places; the bottom of the document, in the column on the right, or in the Notes of Decisions tab at the top. 
  • Lexis Advance - In Lexis Advance annotations are called Case Notes. They are available as you scroll past the statutory text; you can also jump to them by using the "Go to" menu near the top of the screen.

Cases in both are divided by topic to help you find the cases most relevant to your issue. 

Annotated Statutes are not available in Bloomberg Law.

Browsing by Subject

Westlaw: In the Browse box, click the Tools tab and select the West Key Number System. From here you can search the West Key Number System from the search bar at the top or browse the list of 450 topics. If you click through to a digest document (a listing of cases that fall under a specific topic and key number), you select a different jurisdiction at the top of the screen and search within that listing. 

Lexis Advance: Click the Browse Topics option at the top of the Lexis Advance home page.  You will see the topic index for Lexis Advance; you can either search with the search box provided or browse through the list of top-level topics which are further divided into sub-topics. You can add topics to a search or view the Topic Documents (See "Finding Cases using Headnotes").

Finding Cases Using Secondary Sources

Secondary sources, such as legal encyclopedias or the American Law Reports, are great places to start your research and can help you find relevant case law on your topic. 

Legal Encyclopedias: Legal encyclopedias are similar to encyclopedias that you may have used as an undergraduate, except that they focus on brief overviews of legal topics.  Different encyclopedias will have different features, but keeping an eye out for the following will help you locate additional case law:

  • Case supplements - often legal encyclopedia entries in Lexis and Westlaw will include a supplement following the article that lists a few pertinent cases.  You might also look to see whether the article contains an illustration of the subject matter; this would generally involve describing the treatment of this area of law in one or two key cases.
  • Reference lists - some legal encyclopedia entries in Lexis or Westlaw will contain a short list of references.  This could include other secondary source materials, but may also include references to pertinent topics and key numbers in the West Key Number System, a case-finding tool.

American Law Reports: American Law Reports contain in-depth articles on legal topics. Each article has its own table of contents, index, and research references.  You can find relevant cases by looking at the:

  • Table of Cases - breaks down relevant cases, statutes, and court rules across multiple jurisdictions that pertain to the subject of the article. The Table of Cases is labeled slightly differently depending on the database you are using.
    • WestlawTable of Cases, Laws, and Rules
    • Lexis AdvanceJurisdictional Table of Statutes and Cases
  • Research References - This section contains references to a number of materials that can be used to locate additional cases, including West's Key Number Digest, Westlaw databases, other ALR annotations, legal encyclopedias, treatise materials, trial strategy materials, and forms. Research References are labeled slightly differently depending on the database that you are using.
    • Lexis AdvanceTable of References
    • Westlaw -  Research References