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Case Law Research

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

Case Law Research in Print

Key Numbers and the Digest System

How do I search for cases on a certain topic using print resources?

Case law digests are a very powerful tool for conducting efficient case law research using print resources.

West, the chief publisher of the reporter system, developed a system for classifying the content of legal opinions called the key number system.  The key number system created 414 broad legal topics into which all legal matter can be sorted. The broad topics are then divided into more specific subtopics and key numbers, which allow researchers to zero in on very specific legal subject matter.

Key numbers from West's Texas Digest

Example of subtopics and key numbers within the digest topic "Automobiles" from West's Texas Digest - © 2013 West Publishing Company. Click to enlarge.

West editors review cases to identify the important points decided in the opinion and assign them a key number based on the specific legal subject matter addressed. The headnote section of the cases contains relevant key numbers and a brief summary of the legal aspect of the case that relates to each key number. You'll see these headnotes in the database versions of these cases, too.

Headnotes assigned to a case in the South Western ReporterHeadnotes assigned to a case in the South Western Reporter

Example of headnotes and key numbers assigned to a case in the South Western Reporter - © 1980 West Publishing Company. Click to enlarge.

Lexis Advance's system of Legal Topics functions in much the same way by classifying points of law according to their list of pre-determined Legal Topics.

The digest system is a way of finding cases based on subject matter. Digests are arranged by topic and key number. The section for each key number lists the cases that have had that key number assigned to them by West editors as illustrated above. Knowing the key number for the point of law that you're interested in will allow you to locate similar cases by looking up that key number in the digest.

West's Texas DigestWest's Texas Digest

Example of West's Texas Digest entry for Automobiles, key number 20 - © 2013 West Publishing Company. Click to enlarge.


Using Footnotes and Annotations

What are annotations?

If you're not sure what key number is the best one to use, another method for finding relevant cases using print materials is to consult the annotations and footnotes of other resources. Annotations are references to other legal documents or library materials that the editors of the publication have decided are relevant or helpful in further research.

In particular, the start of every section in a West publication contains a set of annotations labeled Library References or Research References. Those include helpful places to turn for more information, including relevant key numbers. You'll see this format in many West publications, including Vernon's Texas Statutes and Codes Annotated. In the example from Vernon's Texas Statutes and Codes Annotated below, which shows a section of the Texas Penal Code and its annotations, the Library References section contains a key number (highlighted in yellow and labeled with a "1" below) that West editors thought was relevant to this statute. You can then take that key number to the digests or Westlaw to find associated cases.

Most importantly when researching case law, annotated statutes will provide a list of Notes of Decisions (highlighted in blue and labeled with a "2" below) that list notable court cases involving that statute. The Notes of Decisions is an excellent place to look when you would like to search for cases related to a statute.

Annotated Texas statutesAnnotated Texas statutes

Vernon's Texas Statutes and Codes Annotated - © 2011 Thomson Reuters​. Click to enlarge.

Please see another example below taken from a legal encyclopedia available in the library called Texas Jurisprudence. Texas Jurisprudence explains and summarizes the law into very brief entries, making it a great resource for those beginning their research. The section shown is about the duty of care of parking facilities and garages. If you had a case regarding negligence by a parking facility, this might be a good place to start looking for more information.

In this example, you will see the Research References section that we saw above in the annotated statutes. The sections highlighted in yellow and labeled with a "1" below are an example of key numbers that the editors felt would be relevant to the topic discussed in this section.

Footnotes in Texas JurisprudenceFootnotes in Texas Jurisprudence

Texas Jurisprudence 3d - © 2015 Thomson Reuters. Click to enlarge.

What are footnotes?

If there are specific cases that are important to the topic, they may be listed in the footnotes. Footnotes are where the editors cite the cases and statutes that form the basis of their summary. You can then use the citations provided to look them up in the case law reporters or legal databases.

See the section highlighted in pink and labeled with a "2" above as an example of cases that were cited because they were instrumental in establishing or refining the rules of law that the author describes in the encyclopedia entry.

Please note that legal databases Westlaw and Lexis Advance also provide annotated documents! Fastcase documents will have limited annotations that usually only refer researchers to relevant cases. This is less information than Westlaw or Lexis Advance will provide, but it will still be very helpful for someone doing case law research.

Print Resources at the Library

These are the most commonly used print reporters and digests. The Texas State Law Library may have other resources in addition to the highlights we present below.