In index usability studies, users consistently find See also cross references confusing. It would seem that not including them would be warranted, except users also get better results when using indexes with See also references. In my earlier post about cross refs (see what I did up there?), I suggested it’s because See also is attached to headings that already include page numbers. Why be directed elsewhere when there is already information at the first point of entry? Why wouldn’t those page numbers be in the first instance?
Well, for several reasons. A See also cross reference, according to Hans Wellisch in Indexing from A to Z, indicates relationships among terms, not exact synonymity. So:
general-to-specific relationships (or the other way around)
vehicles, 4, 72–75. See also cars; trucks
associations among terms such as whole to parts, or related activities
Traditional Chinese Medicine
See also integrative oncology
and occasionally between names, when historical events dictate the specificity
abolition of serfdom
Revolution of 1918
See also Soviet Union
Problems occur when these cross refs are used incorrectly, or for other purposes. A See also should always take the user to new information — the indexing maxim, “Save the time of the user,” has a more blunt version, “Don’t waste the user’s time.” See also should also not split information between synonyms, unless necessary as in the Russia/Soviet Union example (where we can assume there are subheadings for the Cuban Missile Crisis and glasnost under Soviet Union). Don’t do the following:
See also eggplant
See also aubergines
Simply doing a “find all: See” search while editing can cut down on mistakes with cross references. One common problem during the indexing process is putting in synonyms—often because the author uses more than one term interchangeably in the text—as you think of them or come across them. After all, you don’t want to forget to include that term in the index. One way around this is to choose the preferred term for the indexing process and then use See cross references from all synonyms as you think of them. During the edit, these can be easily changed about or deleted—or even double posted (all the same information is under two different headings, but there is no cross reference)—with the “find all” command to make sure they’re all correct.
Doing a better job of using cross references in the indexing process could go a long way toward helping users understand how to they work.