Index Purpose

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Index Purpose

The Purpose of an Index

  • Encourages efficient retrieval of topics
  • Illuminates the author's message with succinctness
  • Groups concepts that are scattered throughout the text
  • Creates structure for the interrelationships between explicit and implicit concepts
  • Can function as a decisive factor in book selection or purchase
Index: Does my book need one? If you are writing or publishing a nonfiction book, this is a question you may be asking yourself. We start with three answers to this question: (1) Book reviewers often look for the inclusion of an index as a sign of quality. (2) Indexes increase sales, both online and in the store. (3) The library market expects a nonfiction book to have an index. 

Positive book reviews: The book reviewer can judge the scope and treatment of a subject from a quality index. If inclusion of an index can help earn your book a positive review from a renowned source, it can prove to be invaluable in increasing sales. The library market is known to rely heavily on positive reviews for purchasing decisions.

Indexes increase sales—Online market: Online browsing of the inside of a book, which usually includes the index, is contributing to increased sales. Google Book Search has significantly increased book sales for Oxford University Press. In 2006, journalist and blogger Cory Doctorow reported that “publishers attending the Frankfurt Book Fair this week have gone on record thanking Google for its controversial Google Book Search program, which makes searchable indices of millions of books available online. They say that making their books visible to Internet users searching for answers converts these searchers into customers. They also say that Amazon's likewise controversial Look Inside program has been good for sales.”

Indexes increase sales—Bookstore market: We all have observed people browsing an index to help them decide whether the book contains the topics they’re looking for. Think about how information-loaded our lives have become and how useful an index is to someone who feels short on time.

Indexes increase sales—Library market: Robert Broadus said in a text on book selection for librarians that “a good index should be expected in any work except creative literature” (53). Richard Gardner, founding editor of CHOICE, had an even stronger admonition: “publishers need to be told that nonfiction works without an index are practically useless in libraries and in the long run will lose sales” (22). And for S. R. Ranganathan, an early expert on library book selection, “to get into a book without an index is like getting into a forest without a trained guide” (100). He was even more passionate when he said that producing a nonfiction book without an index should be an indictable offense!

Librarians are schooled in collection development. From the public school library—such as Baltimore Public Schools, where an index is one of six criteria used to select books to add to their collection—to the local public library or university library, you will find that an index is listed in the criteria library staff are trained to use when making book purchasing decisions.

The library market is large. According to the Institute of Education Sciences, “public libraries had 815.6 million print materials in their collections in 2005.” According to Dan Poynter, the total library market had $5 billion in book sales in 2007. To learn more about library sales statistics and marketing strategies, please see the links to additional articles in the References below.

Index quality: Having established the need for a quality index, we should define what an index is. An index is an information retrieval tool. According to Nancy Mulvany, “An index is a structured sequence—resulting from a thorough and complete analysis of text—of synthesized access points to all the information contained in the text. The structured arrangement of the index enables users to locate information efficiently” (8).

Since we’ve learned that the library market, reviewers, and everyday book lovers judge the quality of an index, we should consider how to create a quality index. Authors sometimes consider using automated “indexing” software to try to produce an index.

Below are two examples of entries from an “index.” The first one is created by software, which can only produce a concordance, and the other is an index created by a professional indexer.

Roosevelt, Franklin D., 5-9, 16, 17-18,
31, 43, 45, 54, 64-65, 68-72, 88, 105-108,

Roosevelt, Franklin D.
...armed forces integration, 64-65
...banking crisis, 5-9
...Civilian Conservation Corps, 265-270
...declaration of war, 16
...GI Bill enactment, 54
...Japanese American internment and, 17-18 foreclosures, 105-108
...New Deal initiatives, 45, 68-72
...USO mobilization, 31
...WAAC legislation, 43
...War Refuge Board formation, 88

Which format do you think readers would prefer to use, a quality index written by a professional indexer or a concordance with a huge slew of page numbers to thumb through? Furthermore, a written index is based on both the author’s implicit and explicit message. No current software can capture an author’s implicit communication. The indexable terms and concepts are chosen during the analysis of the text based on the prospective readers’ need for a useful, structured retrieval tool.

As Olav Kvern and David Blatner recently stated, “Sitting down and indexing a book is—in our experience—the most painful, horrible, mind-numbing activity you could ever wish on your worst enemy. And yet, where this is the kind of task that a computer should be great at, it’s actually impossible for a computer to do a good job of indexing a book by itself. A good index requires careful thought, an understanding of the subject matter, and an ability to keep the whole project in your head at all times. In short, it requires comprehension—a quality computer software, at this early stage of its evolution, lacks.”

To judge or write a quality index, many use the “Index Evaluation Checklist,” which can be found at the American Society for Indexing web page:

Authors as indexers?: Some authors write their own indexes, and others prefer to hire a professional indexer who will bring a fresh eye to the manuscript. The author is sometimes so immersed in their subject that they find it difficult to analyze the text from the readers’ standpoint. Usually the author does not have training or tools, nor will they be familiar with current indexing conventions. Some indexers specialize in technical or professional areas such as medical or law and will have a similar background as the author.

Kvern and Blatner also made this recommendation “Hire a professional indexer. The author of a text is the worst person for the job. You simply know the material too well (or, if you don’t, why in the world did you write the book?) to create a useful index. A professional indexer will read and understand your text, and will create an index that opens it up to a wider range of possible readers than you ever could. It’s what they do.”

Cost: The cost is typically set on a per page basis. The page rate varies depending on a few factors such as: (1) density of text (expected number of index entries per page); (2) complexity of material (technical terminology, footnotes, etc.); and (3) page and font size (as these are book, not manuscript, pages). The indexer prefers to preview 10–20 pages from the midsection of the book to evaluate these factors before giving a firm quote. For example: a 200-page, light trade book with an expected 3 index entries per page might cost about $400–$700, whereas a dense scholarly 200-page manuscript with footnotes might be quoted in the range of $750–$900. Rush deadlines sometimes incur additional fees, so giving the indexer ample lead time will help keep your costs down and help ensure the highest quality index.

Someone once said that a book without an index is like a country without a map!

Article author, Mary Harper of Access Points Indexing, produces print and electronic indexes for authors, self-publishers, large and small corporate publishers, and packagers. She enjoys working as part of an author’s team and can offer flexible payment options.

A special thanks goes to fellow indexers Cher Paul, long-time publishing professional, for her able copyediting and critique of this article, Email: and to Tami Robinson, Associate Professor/Coordinator, Instructional Services, Whitworth University, Washington, for her assistance with the research on the library market.

Baltimore Public Schools, “Selection Criteria for School Library Media Center Collections,” n.d. (accessed June 2009).  

Chronicle of Higher Education, Brock Read on Wired Campus blog, “Some Publishers Warm to Google Book Search,” 2007.

Cory Doctorow, “Google Book Search sells books,” 2006. 

Chris Kahn, “Reaching the Library Market,” 2005.

Dan Poynter, “Statistics on the library market,” Para Publishing, 2007. 

Fern Reiss, “Sell More Books to Libraries,” 2008. 

Institute of Education Sciences, U.S. Department of Education, “Public Libraries in the United States, Fiscal Year 2005” (report). 

Jenny McCune, “Getting Librarians to Buy Your Books,” 2006. 

Olav Martin Kvern and David Blatner, “Working with Long Documents in Adobe InDesign CS3: Indexes (or Indices),” 2009. 

Nancy C. Mulvany, Indexing Books, 2nd ed., University of Chicago Press, 2005.

Richard K. Gardner, Library Collections, Their Origin, Selection, and Development, McGraw-Hill Book Company, 1981.
Robert N. Broadus, Selecting Materials For Libraries, The H.W. Wilson Company, 1973.

S. R. Ranganathan, Library Book Selection, Asia Publishing House, 1966.  

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