An index is an alphabetical, chronological, or numerical arrangement of entries that specify the location of substantively addressed terms and concepts in a document. Similar terms and concepts are interlinked through cross-references.
No. There are many programs that can easily create concordances, but not indexes. Programs that are marketed as being able to create back-of-the-book indexes are in reality concordancers. With these programs a document is scanned and a list of words is compiled, along with their page numbers. The user must analyze each of the results compiled by the program to determine relevancy and inclusion in the index. These programs can manipulate a document, but they cannot understand a document. Properly analyzing a document is a creative process which requires human understanding.
There are powerful dedicated indexing programs that assist in the indexing process (e.g., Sky Index, Cindex, and Macrex). Pharos Indexing uses Sky Index software and/or DEXter for Microsoft Word.
To produce a properly formatted and well-constructed index in a short time frame requires indexing experience, which the ideal indexer has and the author usually doesn’t. Anyone can create an index, but to produce a quality index in a timely manner requires the labor of someone versed in the mechanics of indexing, who can bring an objective pair of eyes to a document and parse the whole for relevant terms and concepts, while keeping the intended audience’s needs in mind. The dedicated indexing software used by most professional indexers is expensive and requires a substantial investment of time to learn to operate efficiently.
Aside from providing users with quick access to specific information, indexes increase sales. Librarians, educators and institutions, as well as the general book buying public, often make purchasing decisions based on the presence of an index and their assessment of its usefulness. In addition, book reviewers are often critical of nonfiction books that lack indexes.