The What and Why of Indexes
What is an Index?
An index is not a concordance, a list of all the words that appear in a document. A concordance lacks analysis and synthesis. It is simply a list of words. [emphasis added]**
The U.S. National Information Standards Organization (NISO)*, in their 2021 Criteria for Indexes, defines an index simply as, “a systematic guide to facilitate retrieval of content.”
According to NISO:
An index increases the findability of content, and facilitates the discovery of information that readers do not yet know about through the connection of related terms.
An indexer determines which information receives major and minor treatment in the text being indexed, and records locations of important information in the index while excluding superficial references which are unhelpful to the reader.
Index as Enabler
The indexer’s job is to present useful and efficient access points to information in the text.**
In short, indexers methodically analyze the text to be indexed and use their judgment, based on indexing expertise and (general) knowledge of the subject material at hand, to create a useful tool for readers, enabling them to efficiently find the information they seek.
*ANSI/NISO Z39.4 Criteria for Indexes (Baltimore, MD: National Information Standards Organization), p.3-4.
**Nancy Mulvany. Indexing Books (Chicago: University of Chicago Press, 2005), p.10; 86.
