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Case digest systems vary considerably: a good topic for further study

In a recent post on slaw.ca, entitled Law Reports, Digests and Public Access to Legal Information, Louis Mirando discussed various considerations regarding whether the Law Library at Osgoode Hall should maintain its print subscription to the Canadian Abridgment Case Digests.

Several interesting issues were raised in his post, or in comments on the post, including

  • whether the print subscription to the Canadian Abridgment should be maintained for archival reasons
  • whether the print subscription needs to be maintained for library users without electronic access, such as members of the public
  • whether students need to use, or at least see, the print version in order to learn how to use the electronic version
  • whether case digests are a useful starting point for research, given the treatises now available
  • whether case digests have become too cumbersome to be useful as a result of trying to digest all cases
  • whether researchers’ reliance on the Abridgment results in them overlooking other digest services and classification schemes, such as the Maritime Law Book National Reporter System key numbers, or Quicklaw’s The Canada Digest

As an aside, I note that after 2006 Maritime Law Book stopped assigning key numbers to trial level decisions from Ontario and BC.

When digests are most useful

I would never start my research with a case digest collection, and recommend that narrative secondary sources be used first. However, I think a digest collection can be very useful in the following circumstances:

  1. as a current awareness tool
  2. to use the classifications assigned to a relevant case to find other cases dealing with a similar issue
  3. where the topical sources for the subject area are poor
  4. where the topical sources have poor coverage of my jurisdiction
  5. to look for cases outside of the date range of the other resources reviewed
  6. to ensure nothing is missed

The frailities of digest classifications

Although I use the digest classification schemes to check for similar cases, I often find that highly relevant cases are not listed under the classification where I would have expected to find them.

Two years ago I compared the contents of a Canadian Abridgment classification with the contents of an equivalent Quicklaw Canada Digest classification, to see how different they were. I was particularly interested because of the number of law firms that are choosing to “single source” rather than subscribing to both Westlaw Canada and Quicklaw.

The classification headings in these two products are quite different, but I selected a classification that was narrow, and which I thought should contain the same cases, dealing with custom elections in aboriginal communities. These are the classifications that I compared.

Abridgment Digests Canada Digest (QL)
Aboriginal Law Aboriginal Law
III Government of Aboriginal people Communities and goverance
2 Self-government – Self-governance
3 Elections – Elections
b Custom – Community custom

Digests comparison

I was very surprised by the results. The Abridgment Digests classification contained a total of 21 digests, and the Canada Digest classification had a total of 16 digests. However, only 4 of the digests were common to both, as illustrated. The most recent cases were in the Canada Digest.

I have not repeated this search more recently, so the numbers would probably be different if the same search were done today.

These results demonstrate the problems with relying on digest classification, and also with using a single source.

How to improve retrieval of relevant digests

One way to improve retrieval rates when searching in digests is to use a broader classification in combination with a keyword search. For example, a search run on all of the digests in the Abridgment under the Aboriginal Law classification, using the search string elect! /s custom! retrieves many more digests. I usually use this method, rather than looking only at the digests under a narrow classification.

Rigorous analysis and evaluation of digest services is needed

I haven’t tried more experiments with comparing digest results, or analyzed the cases that I retrieved to determine which service more accurately classified the cases. However, this would be a great topic for academic study. It could also be done as a legal research class exercise. If you have done this type of comparison, let me know what you concluded.

Addendum

An interesting comparison of American case digests and point of law citator results in Westlaw and Lexis has been published by Susan Nevelow Mart, entitled “The case for curation: the relevance of digest and citator results in Westlaw and Lexis“. Regarding digests, she concluded that the human-indexed Key Numbers in Westlaw gave more relevant results than the algorithmic indexing used in Lexis. For citators, where both systems rely on algorithms to match headnotes, she found that the Lexis Shepard’s algorithm produced slightly more relevant results than the Westlaw Keycite algorithm. However, she found that there was very little overlap in the results, and concluded that neither resource returned comprehensive results.

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