Hello,

What is structure within an index and is it actually important?

I’ve been thinking about this question over the last couple of weeks. There have been parallel discussions on the Indexer's Discussion Group (IDG) and Cindex Users email lists about AI and indexing, in response to Ben Vagle’s announcement of his latest AI indexing tool, Indexia. If you are not part of those email lists, you are welcome to join and go back to read.

You may recall that Ben released a different AI indexing tool earlier this summer, AI-indexing, which I mentioned here. This new tool seems to be an upgrade or a rebrand; I’m not sure how it is different, to be honest. It is described as a “professional indexing assistant,” capable of “generat[ing] a fully structured initial draft with terms, contextual subentries, and page references—giving you a professional starting point in minutes, not weeks.” I believe Indexia is still in the beta stage. I have not tried it.

In the ensuring discussions and Ben’s responses to questions, I was struck by the emphasis on term extraction. In Ben’s program, AI identifies and extract terms, along with their context and locators, which the human indexer can then edit. A “fully structured initial draft” is promised, but what does structure mean in this instance? Looking at the examples on the Indexia website, I wonder if structure actually means format, as in alphabetical sort and punctuation and tabs in all the right places.

I thought again about term selection and structure last week while corresponding with a client. When the author contacted me, they also sent a list of terms that they had already written. I thanked them for the list, and explained that I would take it into consideration while also reading their book and selecting terms myself. The author then asked about my process for creating “the list.” Which is a great question and I was happy to answer. But I was struck by the use of the word “list.” When I index, I don’t think of it as compiling a “list” but rather as writing an index.

In both of these instances, I wonder if there is a misconception that an index is essentially a list. It is as if structure is a byproduct of arranging headings and subheadings in a certain way. No more complicated than that.

Flip through a handful of nonfiction books on your bookshelf and you are likely to find at least one index that does look like a list. There is no, or very little, sense of movement and relationship between terms. There are no, or very few, cross-references. Subheadings may be sparse. All of the headings—names and concepts—exist on one level.

I like to think of those indexes as flat. They give the impression that not much is happening.

For some books, a list-like approach is indeed appropriate. I am not trying to say that every index needs to be complicated. But if the author or indexer assumes that an index is simply a glorified list, then the resulting index is probably not going to be very good. What is missing is a clear structure.

I like to think about structure in terms of the hierarchy of information. Information within any given book is typically layered or nested. At the top is the metatopic, which is what the book as a whole is about. Below the metatopic, often given their own chapters, are the supermain discussions, which are the key facets or arguments of the metatopic. Below the supermain discussions are the regular discussions, which flesh out the supermains. At the bottom are all the little details and examples which further give life to the book.

Mirroring the book, the index should somehow reflect each of these layers. The metatopic, supermain, and regular discussions should each have their own arrays. The relationships between topics and levels should be clear through subheadings or cross-references. Instead of a list, the index becomes an interconnected web, allowing the reader to enter the text through multiple entry points. This is what I mean when I say that the index needs a coherent structure.

What the structure actually looks like for any given index will vary. While I often have an approach in mind when I begin an index, I don’t recommend trying to shoehorn an index into a specific template. It is important to pay attention to how the book is actually written and how the information fits together.

That said, by way of example, here are three different structures for three different types of books:

• A book with a strong, central metatopic, like a biography or a corporate history. This will likely have an extensive metatopic array for the central subject. I don’t like breaking up a person’s life and scattering those chunks throughout an index. Other main topics and details, which can stand alone, would be their own arrays, revolving around the central subject.
• Other books, say a business book on leadership, can more easily be broken down into their constituent supermain discussions. Each leadership quality, in this example, would receive its own array with subheadings. The metatopic array, for leadership, would likely be short, mostly consisting of cross-references to the various qualities. This is a more decentralized structure, anchored by the various qualities.
• Other books may be even more decentralized. A hiking guide, for instance, is essentially a list of hiking trails, along with details of scenic mountains, lakes, or rivers, which readers may also search for. A metatopic array for hiking is probably not useful, unless there is generic hiking advice or safety tips which need to go somewhere. Supermain arrays may also not be relevant, though if the hikes are organized by region or theme, then perhaps those regions or themes should also be reflected in the index. Instead, the emphasis in the index should be on the individual hikes, along with other relevant details. This may end up looking like a list, and that’s okay because it suits the content.

In the three examples above, the index structure varies considerably, from an extensive metatopic array anchoring the index to the emphasis being on all the details. The appropriate structure depends on what the book and audience needs. What remains true in each case is that the choice of structure is deliberate.

When structure is ignored, or assumed to be a byproduct, or thought to be synonymous with format, I fear that the index is not going to be nearly as useful or easy to navigate. A list is fine. It’s also inert, doesn’t indicate relationship or the depth of complexity that exists within a book. I know that the index is supposed to point to information, not reproduce the book, and I think that giving the index a clear and deliberate structure is the best way to point towards information, rather than compiling a list which is easy to gloss over.

A good structure is also part of the value that a human indexer can bring. As human indexers, we do more than extract terms. We can organize and structure those terms to provide context and to facilitate navigation and retrieval. We can go beyond a list.

So be human. Be creative. Be intentional. When writing an index, let structure guide your decision-making, alongside term selection.

If I may dare say, let’s help make the world a better place, one excellent index at a time.

Yours in indexing,

Stephen

​

PS. If you are interested in learning more about the hierarchy of information and about structure, I go into more detail in my book, Book Indexing: A Step-by-Step Guide. You can learn more about my book here.