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Secondary Sources: Key # Digest system

American Digest System

The American Digest System

  • The American Digest System is an outline of the law, broken up into over 414 topics from Abandoned and Lost Property to Zoning and Planning.
  • Digests organize cases topically by subject, making it easier to find the cases you need. Otherwise you would need to search for cases in chronological order!
  • Each case is read by the editors at West and headnotes, summarizing the issues in the case, are added to the beginning of each case. The headnotes are assigned a key number and published in the digests, under the digest topics.
  • The digest finding aids are used to find the key numbers. Once you find key numbers relevant to your research, you can use them in the appropriate digest to find the cases you need for your research.
  • The greatest strength of this system is that topics and key numbers are cross-jurisdictional. It is possible to find cases from any jurisdiction using the same topic and key number.
  • Remember that annotated statutes give you key numbers for related cases.

The Digest System is divided jurisdictionally into four basic "types" of digests:

  • State (including federal cases from the respective states)
  • Regional (Atlantic Digest, North Western Digest, Pacific Digest, and South Eastern Digest)
  • Federal (Federal Practice Digest and United States Supreme Court Digest)
  • National (Decennial Digests and General Digest)

The Digests are kept up to date with:

  • pocket parts
  • semi-annual supplements
  • replacement volumes

Using the West Key-Number Digests

Case in hand. If there is a West reported case on point in hand, use the headnotes and associated key numbers to find more cases on point in any of the other West Digests.

Descriptive Word Index. Use the multi-volume Descriptive Word Indexes to find relevant topics and key numbers.

Topical Outlines & Topic Indexes. Each topic has a broad general outline at the beginning of the topic followed by a much more detailed outline. Review these to find relevant topics and key numbers.

Other Useful Finding Aids

  • Table of Cases: for looking up cases by plaintiff’s name.
  • Defendant-Plaintiff Tables: same as above but listed in order of defendant’s name.
  • Words & Phrases: citations to cases where words or phrases have been judicially defined.

The most common strategy for case finding with a digest is:

  • Begin with the appropriate (narrowest) digest containing the jurisdiction in question.
  • Identify a relevant topic and key number for your research via the topic list in the front of the volumes or via the Descriptive Word Index.
  • Choose digest volumes and supplements you need.
  • Skim outline of topic, read digest paragraphs under relevant key numbers and use citations given at the end of the paragraph to find the relevant cases.
  • Examine recent bound reporter volumes and advance sheets for material not yet found in the updates to the digest.
  • If no cases are found on point, broaden the search by examining jurisdictions outside the jurisdiction question.

Questions, Information, or Demonstration

Contact Reference at 207-780-4351 or email at

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