Keywords Online

A new subscriber emailed the following question, "Are online indexes a list of keywords to search or something different?"

Online "indexes" can take a number of forms:

  • traditional back-of-the-book indexes with hypertext links back to the main document
  • site maps
  • gateway pages with tightly focussed "micro-indexes"
  • "Related topics" at the end of a help topic
Online indexes have the same logical structure as print indexes with main headings and usually subheadings. Some online indexes can also be searched electronically. A search request in Yahoo! returns a list of online category headings. Online indexes, like their print cousins, are true "searchable structures," not simply concordance lists of terms appearing in the text.

The term "keyword" has been used differently in different contexts. The KWIC generator, or Key Word In Context, displays a listing of every instance in the text in which a term appears along with a few words before and after. The resulting list tends to be long and dense. And the entries in the list rarely express very well what is actually being discussed in the text itself. "Keyword," in this application, means the simple appearance of a term in the text rather than a substantive discussion of a particular topic.

"Keywords" in Microsoft Help and many other online help systems are similar to entries in print indexes. Keywords are added manually to a help topic. And like index entries, keywords in this context refer to the general content discussed, not simply to terms that may appear in the text.

In online databases, "keywords" are differentiated from "controlled vocabulary." Controlled vocabulary provides standardized terms for indexing. These terms are stored in a "thesaurus" and are used for indexing all material in the database. For example, in the INSPEC engineering database, you could search using the controlled term "computer aided instruction" and you would find all the articles on that specific subject in that database.

The indexer could also apply ad hoc terms such as "hypertext" or "hypermedia" to specific articles in the online database. These ad hoc terms, known as "keywords," can be significant terms that appear in the text. Or, they can be other terms that describe the material but don’t necessarily appear in the text itself. In either case, these keywords are selected manually and reflect the content of the text.

Online indexes, too, can be constructed from rigorously defined controlled vocabulary or be more ad hoc in nature. Because a thesaurus stores the relationships between terms, controlled vocabulary can be used to suggest other terms that may fit a user’s search better. For example, a user searching under "packaging" could be given the option of using a narrower term such as "encapsulation," "integrated circuit packaging," "plastic packaging" or "semiconductor device packaging." The user could be could also be given the option of searching using a related term such as "seals."

Indexes constructed of ad hoc "keywords" can be quicker to create. Keywords can also add depth to an index created from controlled vocabulary, especially if you are able to search the index electronically.

Fred Brown
Allegro Technical Indexing
(613) 728-9373

June, 2001
Allegro Time!

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