It’s time to dig into cross-references again, picking up where I left off two weeks ago. If you missed that first reflection, you can read it here.

I had a lot more to write than I initially thought about how I use, or don’t use, cross-references, which is why I have split these reflections into two posts. Cross-references are a versatile tool for redirecting readers around the index. They highlight that beyond alphabetical sort, which imposes a default structure, the structure of the index should be deliberate. The decisions on where and how to phrase and place entries should be conscious, to facilitate the reader’s use of the index. Cross-references support that structure by making sure that readers get to the right place. 

Today I’m going to discuss general cross-references, cross-references from subheadings, and cross-references to and from acronyms. 

General Cross-References

Beyond redirecting to specific entries, cross-references can also redirect to a larger category. For example, “Canada… See also specific prime ministers” or “periodic table… See also specific elements.” This works best when readers can reasonably be expected to know who or what might be included in that category, and if there are several headings within that category, leading to a long list if all hits are included. 

If there are only a few possible cross-references, then I think it is better to list them individually. A general cross-reference implies several potential arrays, and if that is not the case, better to be upfront with the reader and not unintentionally mislead. Similarly, if the audience may not be familiar with the category, a general cross-reference could be a dead end rather than a portal.

I do use general cross-references if the above two conditions are met, but I don’t use them very often.  

Cross-References from Subheadings

Cross-references can also be attached to subheadings, rather than being placed at either the beginning or end of the array. This approach is discussed in the NISO Z39.4-2021 indexing criteria, released in 2021, which is when I became more aware of the practice.

I do sometimes include cross-references from subheadings. There are times when that makes the most sense, given the relationship between cross-reference and (sub)heading. Some indexers are proponents of placing cross-references at the subheading level, I think under the rationale that the more granular the placement, the clearer the relationship. There may also be the assumption that readers will be expecting or searching for certain subheadings, even if the information is actually elsewhere in the index.

While I agree that the relationship between cross-reference and (sub)heading should be clear, I also think that arrays should be easy to scan. I also think that given how indexes are typically written, most readers have been trained, through use, to look for cross-references at either the beginning or end of arrays. So while cross-references at the subheading level does have a place, I’m not convinced it is always or often the best choice.

I’ve noticed two problems in how cross-references from subheadings can be used. The first is that cross-references can become buried. They can be more difficult to spot because they are surrounded by other subheadings and locators. 

The second problem is that the array can feel chopped up, especially if multiple subheadings within the array are cross-references. This is often a scenario of cross-references such as, “financial planning: accountants (see accountants); pensions (see pensions); taxes (see taxes)….” For me, that kind of repetition takes up more space and is difficult to scan, especially if interspersed with locators. I think it takes up less space, is easier to scan, and the relationship between heading and cross-reference is still clear if all of the cross-references are gathered together at the end of the array, as in, “financial planning…See also accountants; pensions; taxes.”

So when do I use cross-references from a subheading? I am more likely if there is additional information I want to alert the reader to, as in, “financial planning: accountants and, 34-35, 64, 68 (see also accountants)….” In that scenario, the subheading is necessary for the locators specific to that relationship, and there is additional information elsewhere that I think readers might also want to know. But even then, balancing against potentially burying the cross-reference, I may still place the cross-reference at the end.

Index format can also play a role. Cross-references from subheadings are more likely to be buried and be difficult to scan in run-in format, where there are no visual breaks between subheadings. These problems are less noticeable when using indented format. So when considering where to place subheadings, also consider the impact that format may have on the reading experience.

Cross-References To and From Acronyms

Cross-references can also be used with acronyms. If, for example, there is an entry for “Atomic Energy Commission (AEC),” should there be a corresponding entry for “AEC. See Atomic Energy Commission”?

When I first began indexing, I was meticulous about making sure that headings with acronyms were either double-posted or cross-referenced. I think I saw that somewhere as part of indexing best practices. Until I received pushback from an author. The book was on the health care system in Nova Scotia. It contained so many acronyms. The author pointed out that all of the duplicate arrays made the index far too long and difficult to use, and that most of the acronyms sorted near the spelled-out names anyway. I had another look at the index and decided that the author was right. Since then, I’ve mostly stopped double-posting or including cross-references from acronyms. I don’t think it is necessary.

I do have two exceptions to that rule. The first is if the full name and acronym don’t sort close together. A few years later, I indexed a different book on the health care system in Mexico. Again, a lot of acronyms. This time, I believe the acronyms corresponded to the Spanish name of the organization but the spelled-out name was the English translation. For example, “National Commission for Medical Arbitration (CONAMED).” No relationship between the acronym and full term, and so double-posting or cross-references was important to serve readers searching either way.

My second exception is if I know or suspect that readers are more likely to search for the acronym, or if I’m honestly not sure which way readers will search. In a recent index, the author almost exclusively referred to a number of companies by their acronyms. I’m not sure if those companies are commonly known by their acronyms, but I figure anyone reading the book will probably think of the acronym first, so for those, I decided to either double-post or include a cross-reference. For example, “AEP (American Electric Power)” and “American Electric Power (AEP).” 

As I mentioned above, cross-references are versatile. They reflect that an index is multi-dimensional. An index is more than a list that begins at A and ends with Z. Rather, an index is an interwoven series of entries and arrays which can require navigational aids. Cross-references are the primary means by which to redirect readers to the right place and to additional information.