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Case Law Research

This is a guide explaining how to do effective case law research using online and print resources.

General Information

Case Law Basics

What is case law?

The United States uses a common law legal system. This means that courts and judges have the authority to examine and interpret legal disputes and statutes and then issue legally binding decisions based on their findings. The decisions of the higher courts create precedents (cases that establish a legal rule), which are used by lower courts and legal professionals as a guide to how a law should be interpreted, enforced, or applied from that point forward. The concept that courts should obey the prior decisions of higher courts is known as stare decisiswhich means "to stand by that which is decided."  This principle has allowed the United States to develop a consistent body of case law over time.

Why is case law important?

Judicial precedents allow a researcher to examine how a law has been interpreted and applied in the past with the goal of seeing how it might be applied in the future, or to make a persuasive argument about how it should be applied in a specific situation. 

Case law explained in plain English:

The links below explain the importance of case law in straightforward and easy-to-understand terms. While many are aimed at new law students, they are good sources of information for anyone new to legal research.

How Case Law Is Published

Where can I find case law?

In print: case law reporters

Traditionally, judicial opinions have been collected and reprinted in volumes called case law reporters. Legal publishers print reporters that include cases based on region (for example, the South Western Reporter contains cases from appellate courts in Arkansas, Missouri, Kentucky, Tennessee, and Texas) or by subject (for example, the Bankruptcy Reporter).

The cases within reporters are arranged chronologically, so in order to find a certain case without a specific citation, you need another tool to help you search. Please see the Case Law Research in Print page of this guide for information about how to effectively use case law reporters.

Online: case law databases

In the digital age, legal publishers have created databases like Westlaw and Lexis Advance to allow researchers to locate cases quickly and efficiently. These databases serve many of the same functions as printed reporters do by compiling, organizing, and classifying judicial opinions, but added features like annotations and citators allow a legal researcher to perform much more in-depth research. Westlaw and Lexis Advance are only available by paying monthly subscription charges, which small firms or casual researchers may find to be very expensive.

Fortunately, legal publishers have created more affordable and free case law databases to meet this demand. However, because they are available for low or no fees, they often lack the powerful search tools that make Westlaw and Lexis Advance such popular databases. Using these freely available databases, researchers can still access the complete text of opinions, but they may not be able to carefully refine their searches, browse by subject matter, or determine whether a case is still "good law."

We'll discuss how to make the best use of these databases on the Case Law Research Online page of this guide.

Reading a Case Law Citation

A citation is the shorthand method for showing exactly where a judicial opinion can be located and read. They'll always contain three basic parts and look something like this:

500 S.W.3d 140
Volume number Reporter Page number


The three parts are:

1. Volume number. In our example, 500 indicates the volume number of the South Western Reporter where this case is located.

2. Reporter. In our example, S.W.3d is the abbreviation for South Western Reporter 3d, the reporter where this particular case is printed. If you're not sure what the abbreviation stands for, our librarians can help.

3. Page number. In our example, the final number, 140, tells us that this case is printed on page 140 of volume 500 of the South Western Reporter 3d.

These three pieces of information are all you need to find a case in a printed reporter!

You can also use this citation to find a case in a legal database like Westlaw, Lexis Advance, or Fastcase. Entering this citation directly into the search bar of a legal database will take you right to the text of the opinion.

Determining "Good Law"

What does "good law" mean?

Although our legal system depends on stare decisis (where previous cases create legal precedents), sometimes decisions will be overturned, questioned, or found to be faulty by later cases. Whether or not a case is "good law" depends on whether there have been later court cases finding fault with it or agreeing with it.  Citing to a case that has had other cases disagreeing with it is risky and may put your argument in jeopardy.

How can I find out whether a case is still good law?

Resources that tell you what other cases have said about a particular case are called citators. The most famous citator is called Shepard's Citations - so you'll often see checking the history of a case referred to as Shepardizing. The Texas State Law Library no longer carries any print citators, but there are several options for checking the validity of a particular case online.

Before you rely on a case in a legal proceeding, please see the Important Research Tips page of this guide for tips on how to determine whether your case is still good law.

E-Books from the Texas State Law Library

Our library offers several e-books that go into more detail about case law research. To view these books, you will need to register for a free library account with us.