Card sorting and tree testing are essential UX research methods to optimize information architecture (IA). They help ensure your content is organized in a way that makes sense to users. Here’s a closer look at each method.
Card Sorting
Card sorting is a method where users categorize topics into groups that make sense to them. It’s typically used early in the design process to inform the structure of a website or application.
There are two types of card sorting: open and closed. In open card sorting, participants create and label their categories. In closed card sorting, they sort items into predefined categories.
The process goes like this:
List out main topics or features that will appear on your site.
Give these topics to users on individual cards.
Ask users to sort these cards into categories that feel natural to them.
Analyze the results to identify patterns on how topics should be grouped.
Tree Testing
Tree testing is used to evaluate the findability of topics in an IA. It’s typically conducted after you’ve established an IA, either from card sorting results or other methods.
In tree testing, participants are given a task and asked to navigate through a text-based version of your site’s IA, without any design elements, to find the item or information they need.
Here’s how tree testing works:
Start with a clear IA hierarchy.
Ask participants to locate items using only the labels and structure provided.
Record where they click and how long it takes them to find the item, if at all.
Use the data to identify where users get lost or confused.
Both methods are valuable because they involve real users and focus on content organization without the influence of visual design. They provide insights into mental models — how users expect information to be organized — which can greatly improve navigation and the overall user experience.
Using card sorting and tree testing together can establish a solid foundation for your IA and validate its usability. They are affordable, straightforward, and offer a direct view into your users’ preferences and behaviors.