Why not use a computer?

A human indexer has the capacity to analyse the content and context of the text. An automated computer indexing program can only produce a list of words and phrases occurring in the text (a concordance).


A human indexer can

  • Make an intelligent analysis of a text, disinguishing between significant and important references of use to readers, and passing or irrelevant mentions; and selecting appropriate keywords that users are likely to search under.

  • Recognize relationships with other terms, by providing appropriate cross references that will lead users to other topics or terms that might be of interest eg. literacy see also reading.

  • Provide access to terms for users who search under synonyms by providing cross references eg. pupils see students.

  • Distinguish between homographs (words that look the same but have different meanings) eg. records (best performances) records (audio recordings) .

  • Split long strings of page numbers into useful groups under subheadings

  • Consolidate a number of similar word variations (challenge/challenges/challenged/challenging/testing)  into a single entry point for the user.

  • Analyse graphical and visual items and provide access to the ideas and images represented


A computer program cannot produce such a refined and complex product. Generally an automatically produced index will not be very user-friendly.


Computer full-text searching also has many of these drawbacks, and cannot replace the usefulness of an index, although text searching which incorporates an index has value.