Taxonomy is one of those terms that can feel intimidating at first, especially when most definitions relate to classifying plants and animals. But in UX and information architecture, taxonomy has a very different – and incredibly important – meaning. Whether the concept is new to you or you’re looking to strengthen your IA foundations, this guide will demystify taxonomy and show how it supports better navigation, clearer labeling, and more intuitive user experiences.
What is a taxonomy in information architecture?
In information architecture, taxonomy refers to how information is grouped, classified and labeled within a shared information environment. The overarching structure of that shared information environment is the information architecture (IA) and we find our way around it using the navigation. Think of an IA as a house. The taxonomy determines which pieces of furniture belong in each room and we navigate around the house via doorways and hallways. It all fits together to create one shared environment.
For a website architecture example, think of an online shoe store. The shoes might be organized and labelled by color, size, style, season or collection – that’s the taxonomy. The overall picture of where those groups of shoes live is the IA and in our pursuit of new shoes, we might navigate that structure via a navigation bar at the top of the page. In the amazing Grand Taxonomy of Rap Names visualization below, we can see how the information is categorized, connected and labeled through the lines and the colors. There’s no structure or hierarchy to it yet; that would be the next step in the process to build the IA.
Creating a taxonomy
There are so many different ways to carve information up into a taxonomy and the key drivers for determining that are your content and, of course, your users. Your taxonomy needs to make sense to your users.You may be starting from scratch with a new website or you may have inherited a taxonomy that for whatever reason just isn’t fit for purpose. The first step when creating an initial taxonomy is to do a comprehensive audit of your content. Ask yourself, is your content relevant? Is it up-to-date? Is it all necessary? Are there opportunities to delete or condense content? Once you have your content sorted, you’re ready to move on to the next step of running a card sort with users. Running a card sort early in your taxonomy creation process will allow you to build it up from an evidence based foundation. There’s no point guessing then testing and potentially going back to square one, when you can co-create with your users and then test that informed approach to validate and further evolve your thinking.When you’re designing your card sort, you’ll need to decide if you’re going to do an open, closed or hybrid sort. Here’s a very high level look at what each type involves:
- Open: participants sort cards into groups and name their own categories
- Closed: participants sort cards into categories determined by you
- Hybrid: participants sort cards into categories determined by you AND they can also make up their own.
This early in the taxonomy creation process, it’s best to start out with an open card sort. Not only will this tell you how your users expect your content to be grouped, but will also provide insight into the language and labels that they would expect that content to be associated with. You never know, an open card sort may even surface something you hadn’t considered. At this stage of the process, it’s important to be open to ideas and new possibilities and an open card sort will do just that. Once you’ve settled on the type of card sort you’ll be running, you’ll need to test which can be done through a tool such as Optimal's Card Sorting. It enables you to run unmoderated card sorts remotely (or print out cards for a moderated/in-person card sort!). After your participants have completed your card sort, you can access the benefits of Optimal's powerful result analysis functions.
Learn more about running a card sort and more through our 101 guide.
After you’ve run your initial open card sort with users, you should have everything you need to create the first iteration of your taxonomy. Consider everything you learned during the card sort and cross reference that with your business goals and any tech constraints you might be facing. Don’t stress too much about nailing it this time around, remember this is the first iteration and as you test more and learn more, you can make changes. Build out your taxonomy in Post-it notes with a team and then whack it into a spreadsheet to make future testing and iteration activities easier.
How to test a taxonomy
Now that you have the first iteration of your taxonomy, it’s time to have a go at structuring those groups into an IA and running a tree test. A tree test works like a card sort but in reverse – it allows you to test your thinking by working backwards. Optimal’s Tree Testing is an online tree testing tool that helps you assess the findability of your content without any visual design elements. All you need are clear objectives for what you’d like to learn more about and a spreadsheet version of your draft IA (told you it would come in handy!).
Learn more about Tree Testing and tree testing through our equally handy 101 guide.
Another way to test your taxonomy thinking is to run another card sort. However this time, a hybrid or a closed card sort might be more suitable. A closed card sort would be useful if you’ve got evidence to suggest that your group labels are making sense to users but you’re not 100% sure what belongs in each group. A hybrid sort will let you go one step further and tell you if your content does in fact fit within those labels and if not you’ll also pick up some new ideas to iterate your taxonomy further.
Final Takeaway: How Thoughtful Taxonomy Improves Information Architecture
Developing a taxonomy is much like any other design process: involve your users early, test your assumptions, and continuously refine your structure as your product and content evolve. Taxonomies aren’t limited to digital experiences – we encounter them everywhere, from libraries to supermarkets – and they all serve the same purpose: helping people find what they need quickly and understand how information relates.
In information architecture, it’s the role of UX designers and information architects to shape these systems so they feel intuitive, scalable, and aligned with real user mental models. When grounded in user research and iterated over time, a strong taxonomy becomes the foundation of clear navigation, meaningful labels, and a more discoverable, user-friendly experience.
