Electronic Discovery: Concept Searching & Keyword Searching

Keyword Searching & Concept Searching

In the wake of the DigiCel case, and the constant strides in concept searching (not to mention the hefty marketing budget spendton advertising the tools) does this mean that keyword searching is a thing of the past?

In the preceding article, in which concept searching is discussed,  an example of where concept searching would trump keyword searching was used, this same example is discussed below.

Example 1:

“Do you want to watch football tonight, I bet Chelsea scores?”

Example 2

“Do you want to watch the game tonight, I bet Chelsea scores?”

If the term “football” was used as a keyword, then Example 1 would be found, but Example 2 would not.  But they are both clearly about football. Concept searching tool would be expected to “find” both examples, because “Concept Searching” is, as the name implies, actually looking for “concepts” rather than just keywords.

If a keyword search was to be conducted, then the keyword search list could be expanded to include “game”, but then following sentence would not be found

  • Are you going to see the match tonight?

Therefore the word “match could be added. But what about the  sentence:

  • Fancy a game of footy tonight?

There are, of course, numerous combinations in which a football match can be talked about without mentioning the term “football”.

If a keyword search list was going to be used to identify football, then the keyword list would have to be quite comprehensive, and include the following terms.

  • Football
  • Soccer
  • Match
  • Score
  • Game
  • Footy
  • Five a side
  • 5 a side
  • Players
  • League
  • Cup

This list is not guaranteed to bring every email and document about football back, but it is guaranteed to bring back a lot of none relevant material. It is immediately obvious that the term “cup” and “match” could have lots of meanings, other than football. If the document set is a couple of hundred thousand documents, or even a couple of million, then amount of false positives produced will be huge. In this case the keyword search list would not be very effective.

Concept searching  could cluster the documents of a similar nature together and therefore help to find the football related emails.

In this trivial example we can see the failings of keyword searching and the benefits of concept searching, but that does not mean that concept searching has replaced keyword searching; far from it.

The use of keyword searching in a concept based world

Even if concept searching is used, reviewers will still need to find documents within clusters.  Going back to the football example, once the documents have been clustered a keyword search for “football”, could help identify the relevant cluster.

Equally it may be that there are so many documents to start with that an initial cull of documents with a very broad keyword search, could be justified, before going into a concept based review. Taking a document set from 10 million to 1 million documents, could be seen to be seen as an economical way to approach a review. The reverse is also true, where a concept search could be conducted and then a keywords search applied, to help focus in on the core documents quickly.

The use of keywords will not only depend on the case, but the tools and the service being used.  Some companies will apply keywords, and then only those documents responsive to the keyword search will ever be available for review. Other companies/services will apply the keyword search, after the data was loaded into a review platform. These two different service offerings can make a huge difference to the legal strategy, the results, and the costs.

The next article on keywords will discuss how and why.

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2 Responses to “Electronic Discovery: Concept Searching & Keyword Searching”

  1. Electronic Discovery: What is Concept Searching? « Where is Your Data? Says:

    […] concept searching, should keyword searching still be conducted? This subject will be covered in the next article on concept searching. Possibly related posts: (automatically generated)Electronic Discovery: Concept Searching […]

  2. Electronic Discovery: Using Keywords to Cull? « Where is Your Data? Says:

    […] Discovery: Using Keywords to Cull? October 3, 2009 — 585 The previous article, on concept searching and keywords, ended with the following […]


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