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LRAW Research Spring 2023

Purpose of Secondary Sources

The primary goal of legal research is to efficiently find primary mandatory authority on your legal issue.  Secondary sources are often the best place to begin your research because they include:
     (1) references to primary authorities (statutes, regulations, and cases), and
     (2) commentary on primary authorities to help you understand a specific area of law.

Example: A client presents you with the following facts. A young boy trespassed into a national park to get to a hill well-known for sledding.  On his first pass down the hill, he was severely injured by a tree support wire that was strung from a tree to the ground. He later died of his injuries. Your client, a relative of the boy, wants to bring a wrongful death action in federal court against the National Park Service. The National Park Service claims that the attractive nuisance doctrine cannot apply to allow recovery because it was the sledding hill, not the wire, that attracted the child onto the property. You need to learn more about the attractive nuisance doctrine.


Secondary sources can be particularly useful when researching an area of law that you don't know well. They help you develop search terms to find primary authorities (the law), and help you put your legal issue into context.  There are many types of secondary sources to consult, including:Books in a circle that include Black's Law Dictionary, legal encyclopedias, books and treatises, law review articles, American Law Reports (ALR), and Restatements.

  • Legal dictionaries
  • Legal encyclopedias
  • Books & treatises
  • Law review & journal articles
  • American Law Reports (ALRs)
  • Restatements

Sometimes when you start your research by doing a keyword search for case law (or other primary authorities), you find too many cases to sift through in the time available, or too few cases that are relevant to the situation you're researching, or no case law results. Secondary sources can help in all of these situations. 

  • Too many case law results? Look first at the cases that are cited by secondary sources—these are probably the most important cases on the topic.
  • Too few, or no case law results? Skim secondary sources, looking for (1) other terminology that may be used in court opinions, to help you include more relevant terms in your search, (2) ways to expand your search to include a broader topic area than the narrow focus you might have started with, or (3) explanations that may help you understand why there actually aren't many cases on your topic.

Limitations of Secondary Sources

Before you rely on a particular secondary source, keep in mind that its usefulness may be limited by its currency and comprehensiveness


Because the law can change quickly, it is easy for a secondary source to become outdated.  Always check the publication date of the secondary source you are consulting and update the primary sources it cites to ensure that they are still good law. 

A secondary source may not include everything necessary for your analysis. You must not rely solely on the commentary found in a secondary source, but carefully read the primary sources it cites to determine if they are on point for your precise legal issue.
Secondary sources are a beginning, not an end point.

Also, remember that secondary sources are always persuasive and never binding on courts. Secondary sources are most often used for background, context, and help locating the strongest primary authorities. Secondary sources should not be cited when trying to persuade a court, if binding authority (such as a relevant case decided by a higher court) is available.