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Case Law - What It Is & Where to Find It: Intro



Have you ever had difficulty finding the right case for your research? Are you unfamiliar with the ins and outs of case law or don’t know all the resources available to help you? This guide will show you what case law is and all the tips and tricks to find what you need. See below for introductions on the subjects contained in this guide or click the tabs above for more in depth information.

What is Case Law & Why is it Important?

What is Case Law & Why is it Important?

Case Law is a primary source of law.

Primary sources of law can also include: statutes, constitutions, rules and regulations.

Case law, also known as common law, is the body of law created by judicial decisions.

Case Law is created by the Judicial Branch. Statutes and Constitutions are created by the Legislative Branch. Rules and Regulations are created by the Executive Branch.

The United States' common law judicial system adheres to the doctrine of stare decisis, which requires judges to follow the legal precedent established in previous cases. Therefore, in order to determine what the law is regarding a particular point of law, it is crucial to be able to locate previous controlling and relevant case decisions.

Key Numbers and Headnotes

Key Numbers and Headnotes

Key Numbers: These are unique to products published by West. They represent a specific subtopic within an area of law. They are uniform throughout all West Publications, and are therefore useful in finding primary and secondary resources on the point of law you are researching.

Headnotes: Lexis has a similar feature called Headnotes which show the key legal points of a case. These can be found at the beginning of cases and can be followed to find other cases similar to yours.

Locating a Case by Citation

Locating a Case by Citation

A case citation is a reference to the location of a case in a reporter. These were and still are contained in multi-volume set of books. The case citation can also be used to find a specific case online.

A case citation consists of the case name (i.e. plaintiff v. defendant), volume number, name of the reporter (generally abbreviated), page number and year the case was decided.

For example:

  • Muscarello v. United States, 524 U.S. 125 (1998).
    • The case above be found in Volume 524 of United States Reports on Page 125. This case was decided in 1998.
    • A parallel citation references the location of the same case in more than one reporter:
    • Muscarello v. United States, 524 U.S. 125, 118 S.Ct. 1911,  141 L. Ed. 2d 111 (1998).
  • This means that the case can also be found in both of the following.
    • Volume 118, Supreme Court Reporter, Page 1911
    • Volume 141, Lawyers Edition 2nd Edition, Page 111

If you wanted to find this case you could go to the volume number and flip to the listed page. You can also simply input the volume number, reporter name, and page number (i.e. 524 U.S. 125) into Westlaw or Lexis.

Additionally, if you do not know the whole case name or citation, you can also locate a specific case by party name.



Once you've found a case on point, citators can help you answer the following questions:

  • Is the case still good law?
  • What is the case's judicial history?
  • Can I find additional cases that support my position?
  • Can I find other primary & secondary materials that cite to my case?

Citators can be found on Westlaw, Lexis, and Bloomberg.

For more information, check out our libguide on Citators.



The full text of case opinions can be found in multi-volume sets of books called reporters. Lexis and West also publish unofficial reporters. These reporters contain annotations or editorial enhancements. However, the case opinions are the same as the ones published in the official reporters.

Note: In some jurisdictions, there is no official reporter.

Reporters are organized:

  • Jurisdictionally (Federal or State)
  • Hierarchically (trial court, intermediate appellate court, highest appellate court)
  • Geographically (State or Region)
  • Chronologically

Finding a Case by Keyword

Finding a Case by Topic

If you do not know the name of a specific case. You can also find a case by topic. From either Westlaw or Lexis, you can type your keywords directly into the search bar or you can click "cases" from the list. From there you can further narrow your search by federal or state cases, by specific state, by specific courts or by topic. Specific topics include subjects such as civil procedure, family law, or torts.

Narrowing your search is important not just so you do not receive thousands of results but so you can find authoritative cases for your jurisdiction.


Legal Research Databases

     Legal Research Databases

The two major legal research databases are Lexis and Westlaw. Bloomberg, a long-time business research database, also has its own legal research database. These databases contain case law, statutes, docket information, scholarly articles, and other resources. Lower cost and free legal research databases are also available although they are not as comprehensive or easy to search as the main three. These include FastCase & Casemaker. Google Scholar is a free research resource where you can find legal articles or articles in other subject areas, as well as case law. However, it does not currently include a citator.