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LIS 530 GLE: Legal Resources: Week 4: Intermediation

Adapted from the LibGuide for LAW 627, the 1L course in legal research, this guide is intended for students enrolled in LIS 530 GLE, Legal Resources. It has been edited for course length as well as scope/audience.


Intermediation literally means "to come between."  An intermediary is a person who helps someone attain their goal.  

In legal research, intermediation is the term we use to describe the systems and tools that make it easier to find the most relevant legal information. These include Secondary Sources generally, as well as stand-alone indexes, digests and systems that are intended to help users navigate through law more efficiently.


American Jurisprudence 2d is a Legal Encyclopedia, providing coverage of the whole of American Law in one large set of books (or database). It is arranged like a general encyclopedia, beginning with large legal topics like Divorce or Criminal Procedure. These topics are arranged throughout the set in alphabetical order. Users are intended to approach the set, choose a relevant topic, select the volume or volumes that cover that topic, and browse the outline for the topic to read more. What they'll find is much like a traditional encyclopedia "article" or story, with an introduction and story and lots of cases cited to illustrate the points in the story.

Legal Encyclopedias have limited use in practice. They are most useful to law students and others who are learning the law, as they provide a quick way to get an introduction in any area of the law in one publication. The introductions found there are more trustworthy than most anything that could be found on the open web.. Many law libraries have cancelled their print subscription in reliance on their Westlaw access, but that leaves public patrons out. AmJur2d is a great source for a public library or a general university library to own, if a law library is not available nearby.

Law Reviews or Law Journals are scholarly publications containing articles written by law professors, judges and occasionally law students. They are usually theoretical and argue for the re-envisioning of some area of the law. 

Law professors must publish in law reviews to get tenure at their institutions; each law school maintains at least 1 (and usually 2-4) journals (one of which is called the (school name) law review and the others usually adding a subject specialty). These are quite different from the journals of other disciplines, as they are edited by students and published at the school (through a commercial printer -- NOT a commercial publisher). They are inexpensive for libraries to purchase, but can be expensive to manage, as they consist of so many pieces. The Hein Company is the designated agent for back issues of nearly all U.S. law reviews, and they maintain a digital backfile on their Hein Online platform as well. 


The most powerful tools in an attorney's toolkit are those that provide synthesis among multiple sources of the law: statutes, regulation, and caselaw. These are sometimes called Specialized sources, and include Looseleafs and Practitioner Treatises.


The United States Code and the Code of Federal Regulations are both organized in an outline structure, with the top-level divisions running along major topics. While not technically intermediation, these structures do assist users in finding what they need.

The West Key Number System is a taxonomy for American Law -- specifically, for American caselaw. Every case published by West is provided with at least two headnotes (written notes about a point of law in the case), which are assigned to the appropriate topics and key numbers, respectively. For more on taxonomies, see this piece from the Accidental Taxonomist's blog.

LexisNexis has its own taxonomy, but it lacks the reach/adoption of West's topic and key number system, and is generally judged to be less powerful.


There are several indexes for scholarly articles about the law (also known as law reviews or law journals). Many of these journal articles describe the current state of the law in a way that is much easier to understand than the text of the law itself. 

The indexes include the Index to Legal Periodicals (Wilson's) and the Current Law Index, also called the Legal Resources Index when hosted by LexisNexis and Westlaw and Legaltrac when sold as a stand-alone database (as part of the Infotrac system).

Sadly, indexes get no love these days, as search engines' power grow and people get more and more accustomed to using them. Indexes can be most powerful in research when you're looking for the scholarly communication around an issue at a particular time (e.g., just after the appointment of a particular Supreme Court justice, or after the passage of a major piece of legislation).

The West Key Number System

West Topics and Key numbers are like subject headings for judicial opinions. Every Headnote in every case published by West (now ThomsonReuters) is assigned a Topic & Key Number.  Each case has at least two headnotes, reflecting the fact that a case can be about more than one issue.   

For online research, the topics have all been assigned numbers, which are used for sorting instead of strict alphabetical order.  

In the example below, the topic Eminent Domain has been assigned the number 148:

148 Eminent Domain West Key 61

The picture of the key becomes the letter "k."

So the complete online key number reads:  148k61

Here is a brief excerpt of a headnote with a topic and key number assigned to it: Note that the "In General" at the bottom right is a subsection of "Taking for Private Use." It's not clear from the display, but the contents of the topics are arranged in a hierarchical outline. Instead of using subsection and subsubsection numbers, however, they number all the points of law sequentially.   

WestlawNext Digest Field for the topic of eminient domain. Right side of image shows Headnote 1 for eminent domain case example. Lower right of image shows the key number outline. Key number 148: Eminent Domain. Below, 148l: Nature, Extent, and Delegation of Power. Below that, 148k60: Taking for Private Use. Below that, 148k61: In General.


This page will provide you with an overview of  the concept of INTERMEDIATION, both what it means and how it is used in the context of legal research.

At the end of this lesson you should be able to:

  • Define the term "intermediation"
  • Explain the role intermediation plays in legal research
  • List examples of systems and tools that will help you find relevant legal information