Welcome back to another Q&A, on the last Tuesday of the month. How are we already at the end of April?

Today’s question is about granularity:

How should I judge what level of granular information the reader will be looking for? Too many subheadings with the same locator is a red flag. Is there any other good marker? How do I know if it is too granular, or not granular enough? 

That is an excellent question. Thank you for asking.

I suspect this is a common issue that many indexers face. Part of the challenge is that the answer is so often, “It depends!” It depends on the audience, on the subject matter, on the type of book, and how much space is reserved for the index. Because there are so many factors involved, I’m not sure if I can give a satisfactory answer, but I’m going to give it a try.

What is Granularity?

To begin with, what is granularity, anyway?

Granularity refers to the level of detail. In indexes, this is how detailed entries and arrays are. The level of granularity can vary, from large or wide-angle details to small, specific details. When discussing how granular an entry or index should be—whether it is too granular or not granular enough—this is what we are talking about, the level of granularity. 

As I discuss in my book, I like to conceptualize granularity in terms of the hierarchy of information. Most books contain multiple levels of information, which can be mirrored in the index. At the top—the broadest level of information—is the metatopic, which is what the book as a whole is about. Below that are the supermain discussions, which are the main arguments or points which compose the metatopic. Below those are the regular discussions, which continue to break down the main discussions. At the bottom are the small, specific details which further support and illustrate. Each level is a different level of granularity. 

My view is that all levels of the hierarchy of information should be in the index. A well-written index should be balanced. It is not a question of finding the single correct level of granularity, but of creating entry points for all levels. 

Indexing at multiple levels of granularity provides a number of benefits. It serves different readers, both those searching for specific details and those searching at a broader level. Multiple levels of granularity can also facilitate navigation through the index, whether through nesting more granular subheadings under broader main headings or cross-references from broader to specific arrays. Including both broad and specific headings and subheadings also helps readers—and indexers—avoid getting lost in the weeds. Where I’ve seen granularity go wrong is when the index is primarily a collection of specific details, such that it is difficult to see how the details relate to each other or why they are relevant. Small, specific details can definitely be relevant and important to index, but they also need context, and readers also need context. Indexing at all levels of granularity provides that. 

Telling Stories

I like to think about indexing as telling a story. Each array encapsulates what the book has to say about that particular subject. Especially if the array contains subheadings, the subheadings need to work together to present what the book has to say.

Granularity can factor in a couple of different ways.

One is the appropriate length of ranges. A common rule of thumb is to add subheadings if a discussion extends beyond five pages. This is generally good advice, as searching more than five pages can be a big ask for a reader. But what if the range is seven or eight pages? What if there are no clear points within that range to differentiate into meaningful subheadings? What is space is tight? What if one or more pages are mostly filled with figures? Instead of treating those five pages has a hard limit, I treat it as a guideline. My first goal is to see the whole discussion in context. Sometimes, indexing to the full discussion, even if that means a slightly longer range, is enough. A broader level of granularity points readers to all they need to know.

Another way to consider granularity and storytelling is to consider how broad or specific subheadings can be. If the array is for a supermain discussion, some of the subheadings should probably be for regular discussions. Subheadings can be used to nest levels of granularity. 

To be clear, I am not suggesting that all subheadings need to be of the same granularity or that all subheadings need to be one level below the main heading. Subheadings can serve different purposes, and different types of subheadings can coexist within the same array. It is okay to mix in a few specific details or relationships to other supermain discussions, for example. What I am saying is to pay attention to the story that the array is telling, which is most clearly told in terms of the main points made about the subject and in terms of the relationships between that subject and other subjects. These main points and relationships can often be mapped to levels within the hierarchy of information, which is to say, levels of granularity. 

Spreading Out Granularity

So an index can contain different levels of granularity, and levels of granularity can be used to tell stories and indicate relationships.

Entries and arrays for different levels of granularity can also be spread out throughout the index. It is not always necessary to fit all possible subheadings under a main heading.

Say the array is for a supermain discussion. The book  makes seven main points—regular discussions—about the supermain discussion. Each of those points can become a subheading, which combined provides a solid overview of the subject. Each of those seven points can be further broken down into specific people quoted and illustrations made, but do those people and illustrations need to be in this array? I would suggest not. Keeping this array at a broader level of granularity allows it to be clear and compact. Readers will still find those smaller details if they read through to those pages. Those details can also be standalone entries elsewhere in the index, still findable if readers are looking for them specifically.

I hesitate to be too prescriptive here because every book, index, and array is different. Sometimes arrays do function as a place to gather certain types of detail and it is important to get every mention. But my point remains: levels of detail can be spread out. All information should be findable in the index; it does not all need to be findable in the same place. Play around with how granularity is distributed throughout the index. What can be double-posted? What doesn’t need to be double-posted? How can cross-references be used? What is the function, or story, of each array? 

Audience and Type of Book

The level of granularity can also be affected by the audience and type of book.

I know the common advice is that trade books can be more lightly indexed than scholarly books. I think that is true-ish. My tendency is to write comprehensive, detailed indexes for both trade and scholarly books. Perhaps better to say that scholarly books tend to contain more detail, which lends itself to a more detailed index, while trade books can—but not always—be written in broader strokes. When indexing, match the level of granularity to the book.

How the book is written, and the subject matter, can also affect granularity. Some books are written as broad overviews, whether covering a wide time period, or multiple people, countries, or organizations. For these, keeping subheadings at a broader level can be helpful to prevent the reader—and the indexer—from getting lost in the details. Similarly, if an array has a lot of subheadings—say for a main character or key organization—keeping subheadings at a broader level can be a way to cut down on the number of subheadings needed. Subheadings should still be clear and specific—indexing at a broader level should not be mistaken for being vague. Rather, indexing at a broader level means pointing towards the larger point or context. Specific detail may be better suited for standalone entries. 

How books will be used can also impact granularity. Reference books, for which the index will be a primary entry point, should contain detailed indexes, with lots of subheadings and entry points. Scholarly books often fall into this category as well. Books that are written more as a light or casual read are probably fine with a less granular approach. 

Space Constraints

Space can be a real issue for some indexes. There are not enough lines for the index you want to write. This affects granularity. I think it is still important to try to include entries at all levels of granularity, but if space is a constraint, some entries will need to be cut and compromises made.

If space is tight, I tend to prioritize the big picture. I want the supermain and regular discussions to be clearly present. These are the main points that the book makes, and in my view, the most relevant for readers to find.

Indexing at a broader level can also help save space because the broader entry can incorporate or cover multiple smaller entries. Say there is a discussion about railways, which includes mentions of multiple railway companies. In an ideal index, both “railways” and the specific companies are picked up, but if space is a constraint, I choose “railways” and leave out the specific companies. Readers will still find those companies if they search under “railways,” whereas if I only include entries for the specific companies, readers will have a harder time seeing the whole picture. 

Another consideration is how close or far an entry is from the metatopic. The closer to the metatopic, the more willing I am to keep entries for specific details. The further apart, the more likely I am to cut and instead rely on entries at a broad level. 

When space is tight, I also tend to use fewer subheadings and I allow longer strings of locators. I still try to include subheadings if more than ten or twelve locators, as I don’t want undifferentiated strings to be too long, but subheadings take up space and I’d rather squeeze in more main entries. This is another way to be less granular, by removing the clarity that subheadings can provide. Not ideal, but it can be a worthwhile compromise.

 

Finding the right level of granularity can be tough. The first challenge is learning to see the different levels. Once you can identify them, it becomes easier to zoom in and out, and to decide how different levels should fit together and be distributed.

To close, I want to reiterate that there is no single, perfect level of granularity that an index should be at. Indexes should contain multiple levels of granularity, and the right mix of levels will depend on the audience, the subject matter, how the book is written, and how much space the index has to play with. But once you can see the different levels, and to see the levels as tools or as building blocks, granularity can be a valuable lens through which to see and construct an index.