10 Tips to help you evaluate an index for quality

Ensure that key details are reflected in the indexThe book you have spent so long writing and editing is almost ready to be published. It is in its final layout, and has been proofread multiple times. The one hurdle remaining is the index. Finally, you receive the index manuscript for review. While it may be tempting to give the index just a cursory glance before blessing it with your imprimatur, it is worth investing a modest amount of time to ensure that the index does your book justice. A complete and well-constructed index adds real value to your book by making its content more accessible to readers. How can you be confident that the index you receive is good enough for your book?

Here are 10 tips to help you evaluate an index for quality:

1) Leaf through the pages and locate some important concepts and confirm that they are reflected in the index. The major ideas and concepts discussed in your book should be easy to find in the index. Be aware, however, that an index is not a concordance, and will not necessarily include a concept every single time it appears in the text.

2) Glance at main headings that are broken down into subheadings. In a physics text, such a heading may be “mass.” Do the subheadings break down the heading topic into manageable “chunks” (e.g.: “conservation of,” “definition of,” “and energy”)? Red flags include multiple subheadings all from the same one or two pages, long page spans for main headings with no breakdown, and headings followed by long strings of page numbers with no breakdown.

3) Look for the major headings (those with lots of subheadings).  Will they be easy for the user to find, either by being listed under a keyword or via effective cross-referencing (“See” and “See also”)? If there are multiple acceptable terms for the same concept, cross-references should direct the user to the correct heading.

4) Ensure that key details are reflected in the index. In particular, glossary terms and emphasized (italicized) terms should be included in a consistent manner. Significant personal names and organizational names should be included. If there are severe length restrictions on the index due to production requirements, it is more important for major concepts to be included rather than every last detail.

5) Verify the index is balanced (i.e., not “top-heavy” where most of the index references come from the first half of the book). Make sure the indexer didn’t “run out of steam” halfway through the book. There may be special cases where most of the indexable material comes from the first half of the book, so keep this in mind.

6) Spot check accuracy of a few dozen page numbers (locators) in the index. Usually this will be enough to reveal any serious problems. If numerous page locators appear to be incorrect, inform your editor immediately.

7) Verify that the index is pleasing to the eye. Although there are occasionally exceptions, headings with subheadings should have at least two subheads. Spelling and grammar should be correct. Subheadings should be unambiguous in their relationship to the main heading. The language and style of the index should be appropriate to the intended audience. The style of an engineering reference’s index will be very different from a trade book on closing the sale. The former will tend to be more formal, while the latter will tend to be more conversational.

8) Verify that compound terms are listed under multiple access points. For example, “cash basis of accounting” and “basis of accounting, cash.” Both “cash” and “basis” are key terms in accounting.

9) Check for a head note, where appropriate. The head note explains guidelines for using the index, for example, that photos are indicated with italic page locators (323), or that figures are indicated with italic f (323f).

10) The number one criterion in evaluating the quality of an index: does it do its job? The index exists to help the user find relevant material quickly and easily. If it performs this function well, the index is right for your book.


Steve Ingle is the owner of WordCo Indexing Services, located in Norwich, Connecticut. He will present a session entitled “Getting the Best Index for Your Book” at TAA’s 30th Annual Conference in Providence, Rhode Island, June 9-10.