Definition: The classification of something.
Also referenced as: Taxonomies (noun) Taxonomic (adjective)
Related to: Associated, Category, Choice, Classification, Complex, Facet, Flexible, Heterarchy, Hierarchy, Hypertext, Information Architect, Information Architecture, Label, Navigation, Order, Organize, Pattern, Rules, Sequence, Shallow, Structure
Taxonomy is how we arrange things.
When you set out to arrange something, how do you decide where the pieces go? Is it based on what looks right to you, what you believe goes together, or what someone told you to do? Or maybe you let gravity or the alphabet determine the order?
To effectively arrange anything, we have to choose methods for organizing and classifying content in ways that convey the intended information to our intended users.
Structural methods for organization and classification are called taxonomy.
Common examples of taxonomies include:
- The scientific classification for plants, animals, minerals, and other organisms
- The Dewey Decimal system for libraries
- Navigational tabs on a website
- Organizational charts showing management and team structures
We combine taxonomies to create unique forms.
Taxonomies shape our experience at every level. We use taxonomies to make sense of everything from systems to objects. It often takes multiple taxonomic approaches to make sense of a single form.
A Form is the visual shape or configuration something takes. The form is what users actually experience.
Even a simple form like this book uses several taxonomies to help you read through the content, understand it, and use it.
A few taxonomies in this book:
Sorting is easier than deciding how to sort.
Sorting is the act of arranging content according to established rules. The act of deciding how to sort something within a taxonomy is called classification.
If you have a large pile of things, it may take a lot of time to sort through them. But sorting isn’t the hard part. Classification is.
Think about sorting a bag of groceries into a pre-arranged pantry. Everything has a place. You’re simply following the plan. Easy, right?
Now unload that same bag into a kitchen without rules for where things go. How much longer would it take you? How much more frustrating a task would it be? How much variation would you get when the next person unloads groceries?
Sorting is easy when clear rules are in place. But without those rules, assumptions take over and things end up in places where they can be harder to find.
The most challenging part of classification is working with other people to agree on a set of rules.
Ambiguity costs clarity; exactitude costs flexibility.
The more ambiguous you are, the more likely it is that people will have trouble using your taxonomy to find and classify things.
For every ambiguous rule of classification you use or label you hide behind, you’ll have to communicate your intent that much more clearly.
For example, what if I had organized the lexicon in the back of this book by chapter, instead of alphabetically? This might be an interesting way of arranging things, but it would need to be explained, so you could find a term.
The more exact your taxonomy becomes, the less flexible it is. This isn’t always bad, but it can be. If you introduce something that doesn’t fit into a category things can get confusing.
Because there are many words for the same thing, exact classifications can slow us down. For example, I recently tried to buy some zucchini at a grocery store. But it wasn’t until the clerk in training found the code for “Squash, Green” that she could ring me up.
The way you organize things says a lot about you.
Classifying a tomato as a vegetable says something about what you know about your customers and your grocery store. You would classify things differently if you were working on a textbook for horticulture students, right?
How you choose to classify and organize things reflects your intent, but it can also reflect your worldview, culture, experience, or privilege.
Those same choices affect how people using your taxonomy understand what you share with them.
Taxonomies serve as a set of instructions for people interacting with our work.
Taxonomy is one of the strongest tools of rhetoric we have. The key to strong rhetoric is using language, rules and structures that your audience can easily understand and use.
Taxonomies can be hierarchical or heterarchical.
When taxonomies are arranged hierarchically, it means that successive categories, ranks, grades, or interrelated levels are being used. In a hierarchy, a user would have to select a labeled grouping to find things within it. A hierarchy of movies might look like this:
- Romantic comedies
- Classic comedies
- Slap-stick comedies
Hierarchies tend to follow two patterns. First, a broad and shallow hierarchy gives the user more choices up front so they can get to everything in a few steps. As an example, in a grocery store, you choose an aisle, and each aisle has certain arrangement of products, but that’s as deep as you can go.
A narrow and deep hierarchy gives the user fewer choices at once. On a large website, like usa.gov, a few high level options point users to more specific items with each click.
When individual pieces exist on one level without further categorization, the taxonomy is heterarchical. For example, each lettered box in the arrangement in this illustration is heterarchical.
Taxonomies can be sequential.
Sequence is the order in which something is experienced. Some sequences happen in a logical order, where the steps are outlined ahead of time.
Other sequences are more complex with alternative paths and variations based on the circumstances, preferences, or choices of the user or the system.
These are all examples of sequences:
- A software installation wizard
- New patient sign-up forms
- A refund process at a retail store
- A job application
- A recipe
- A fiction book
- The checkout process on a website
Like any taxonomy, the categories and labels you choose affect how clear a sequence is to use.
Hypertexts bridge taxonomies.
We use hypertext to connect things without necessarily placing them together.
Hypertexts are fundamentally different from hierarchical, heterarchical, and sequential taxonomies, because they don’t change where things are located, just how they’re found.
We use hyperlinks to allow users to jump between taxonomies instead of duplicating or moving content. For example, we might hyperlink the bolded words throughout this book. If a user clicks on one of them, we could take them to a definition in the lexicon. We’re moving the user to the content instead of repeating it.
A signpost directing you to a store around the corner is also hypertextual, because it sends you to a specific location without changing the location of the store.
Similarly, websites use hypertext to link to content without needing to repeat it.
Most things need a mix of taxonomic approaches.
The world is organized in seemingly endless ways, but in reality, every form can be broken down into some taxonomic patterns.
Hierarchy, heterarchy, sequence, and hypertext are just a few common patterns. Most forms involve more than one of these.
A typical website has a hierarchical navigation system, a sequence for signing up or interacting with content, and hypertext links to related content.
A typical grocery store has a hierarchical aisle system, a heterarchical database for the clerk to retrieve product information by scanning a barcode, and sequences for checking out and other basic customer service tasks. I was even in a grocery store recently where each cart had a list of the aisle locations of the 25 most common products. A great use of hypertext.
A typical book has a sequence-based narrative, a hierarchical table of contents, and a set of facets allowing it to be retrieved with either the Dewey Decimal system at a library, or within a genre-based hierarchical system used in bookstores and websites like Amazon.com.