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Legal Research Fundamentals

The Different Types of Case Law Research

Generally, there are two types of case law research:

  1. Determining the case law that is binding or persuasive regarding a particular issue. Gathering and analyzing the relevant case law. 
  2. Searching for a specific case that applies the law to a set of facts in a particular way. 

These are two slightly different tasks. However, you can use many of the same case law search techniques for both of these types of questions. 

This guide outlines several different ways to locate case law. It is up to you to determine which methods are most suitable for your problem. 

Popular Case Law Databases

When selecting a case law database, don't forget to choose the jurisdiction, time period, and level of court that is most appropriate for your purposes.

Note: Listed above are the databases that law students are most likely to use. It's possible that, once you leave law school, you will not have access to the same databases. Resources such as Fastcase or Casetext may be your go-to. For any database, take the time to familiarize yourself with the basic and advanced search functions. 

Using Secondary Sources

Check out the Secondary Sources tab for information about how to locate a useful secondary source. 

Remember: secondary sources take the primary source law and analyze it so that you don't have to. Take advantage of the work the author has already done!

One Good Case

What do we mean by 'one good case'? 

A case that addresses the issue you care about. We can use the citing relationships and annotations found in case law databases to connect cases together based on their subject matter. You may find such a case from a secondary source, case law database search, or from a colleague.

How can we use one good case? 

1. Court opinions typically cited to other cases to support their legal conclusions. Often these cited cases include important and authoritative decisions on the issue, because such decisions are precedential. 

2. Commercial legal research databases, including Lexis, Westlaw, and Bloomberg, supplement cases with headnotes. Headnotes allow you to quickly locate subsequent cases that cite the case you are looking at with respect to the specific language/discussion you care about. 

3. Links to topics or Key Numbers. Clicking through to these allows you to locate other cases with headnotes that fall under that topic. Once you select a suitable Key Number, you can also narrow down with keywords. A case may include multiple headnotes that address the same general issue.

4. Subsequent citing cases. By reading cases that have cited to the case you've started with, you can confirm that it remains "good law" and that its legal conclusions remain sound. You can also filter the citing references by jurisdiction, treatment, depth of treatment, date, and keyword, allowing you to focus your attention on the most relevant sub-set of cases.

5. Secondary sources! Useful secondary sources are listed in the Citing References. This can be a quick way to locate a good secondary source. 

NOTE: Good cases may come in many forms. For example, a recent lower court decision might lead you to the key case law in that jurisdiction, while a higher court decision from a few years back might be more widely-cited and lead you to a wider range of subsequent interpretive authority (and any key secondary sources). 

From an Annotated Statute

What is an annotated statute?

An annotated statute is simply a statute enhanced with editorial content. In Lexis and Westlaw, this editorial content provides the following: 

Historical Notes about amendments to the statute. These are provided below the statutory text (Lexis) or under the History tab (Westlaw). 

Case Notes provided either at the bottom of the page (Lexis) or under the Notes of Decisions tab (Westlaw). These are cases identified by the publisher as especially important or useful for illustrating the case law interpreting the statute. They are organized by issue and include short summaries pertaining to the holding and relevance are provided for each case. 

Other Citing References allow you to locate all other material within Lexis and Westlaw that cite to the statute. This includes secondary sources (always useful) and all case law that cites to that specific section. You can narrow down by keywords, jurisdiction, publication status, etc. In Lexis, click the Shepard's link. In Westlaw, click the Citing References tab.

AI and Smart Searching

Lexis, Westlaw, and Bloomberg are all actively developing tools to lead you to cases more quickly. These include: 

Westlaw Edge's recommendations and WestSearch Plus. These will show up in the "Suggestions" option that appears when you start typing into the search bar. 

Lexis Ravel View. When you search the case database in Lexis and click on the Ravel icon, you will see an interactive visualization of the citing relationships between the first 75 cases that appear in your results list, ranked by relevance.

Bloomberg's "Points of Law" feature in the Litigation Intelligence Center also allows users to visualize the citing relationships among cases meeting their search criteria.