What is card sorting?

Card sorting is a well-established user experience (UX) research method where participants group topics into categories according to criteria that makes the most sense to them. 

It’s often used to help inform the IA of a site or app. By giving your participants labeled cards to sort, you can gain useful insights into how and why they group content in certain ways. And creating an IA that’s intuitive is essential to providing a positive user experience. 

The observations you can gain through card sorting can also help you identify trends and decide how to categorize your content in ways that align with the mental model of your participants. 

There are three types of card sorting techniques:

• Open card sort: Participants sort cards into categories that they determine, and label each category themselves.

• Closed card sort: Participants sort cards into predefined categories.

• Hybrid card sort: Participants sort cards into predefined categories, and can also create their own categories.

We’ll dig into these techniques in more detail below.

You can run a card sorting session in person using physical cards, or remotely using online tools like Lyssna. In this guide, we’ll largely be focusing on the latter.

What is card sorting used for?

Card sorting is beneficial when you want to understand how to:

• Sort items into categories, typically website pages or product offerings.

• Choose helpful labels for those categories.

Say you’re creating an e-commerce furniture site. Would your customers expect to see desks, office chairs, and shelving listed as separate categories? Or are they more likely to navigate to ‘home office’? How would readers of your food blog expect to see recipes sorted – by meal type, course, cuisine, diet, season, and ingredient?

You might use card sorting when you want to:

• Make an informed decision about the IA of your site or app. You can use card sorting when building a new site, or improving or adding a new section to your existing site. By asking your target audience to arrange items, you can discover how people understand different concepts.

• Quickly gain research insights. Remote card tests are affordable, simple to create, and easy to recruit and share with participants. Online card sorting tools have reporting capabilities built in, so you can view, sort, and analyze data quickly.

• Discover the mental model of your target users. A mental model is what users know about a system, like your website. Card sorting can offer useful insights into the perspective of your users. For example, how they would prioritize new features or how they would name something. 

Types of card sorting

Let’s explore open, closed, and hybrid card sorting in more detail, and some of the use cases for each method.

Open card sorting

In an open card sort, you create a list of cards and ask participants to define and label categories to sort them into. The participants are free to create any categories they like, and might choose to differentiate the cards in a range of different ways.

Open card sorting uses a generative research method, which means that it aims to gain a deep understanding of your users and their experiences in order to create solutions or innovations for them. It’sgenerally used when creating a new IA from scratch, or improving the IA of an existing site or app. 

You might use this method to get ideas for:

• Organizing products in your ecommerce store.

• Categorizing content on your blog or learning site.

• Organizing products, features, and solutions for your SaaS site.

• Categorizing booking options on a travel site.

• Structuring help center documentation.

Closed card sorting

Closed card sorting uses an evaluative research method, which means that data is collected to evaluate a product or problem and inform the solution.

In a closed card sort, you create a group of cards and ask participants to sort them into predefined categories.

Closed card sorting won’t show you how participants conceptualize categories, but it will help you evaluate how well an existing category structure supports content from their perspective. For this reason, closed card sorts are used when you want to add new content to your existing site, or gain further insights after an open card sort. 

You might use this method to:

• Validate whether participants understand how you’ve categorized content.

• Highlight unclear or misleading category labels.

• Prioritize and rank features and products based on set criteria.

• Define a value proposition (e.g. by asking your customers what matters most to them using criteria like must have/should have/nice to have).

Hybrid card sorting

As the name suggests, hybrid card sorting is a mix of open and closed card sorting methods. Participants can create and label new categories and organize cards into predefined categories.

Hybrid card sorting is beneficial when you want to gain new insights into how your audience sorts content and validate how content is organized. It’s a useful method when adding new content to an existing information architecture.

(Please note that closed and open card sorting is available in Lyssna, however hybrid isn't. Please get in touch if you'd like to request this feature.)

Moderated and in-person card sorting 

A moderated card sorting session involves a moderator conducting and overseeing the activity. Moderators brief participants at the start of the session and ask them follow-up questions at the end to gain qualitative insights. 

Moderated sessions are commonly run in person and can be conducted in a group or one-on-one setting. Topics are written on physical cards and participants organize those cards into groups. The advantage here is that the process is simple and flexible. Participants can sort and move physical cards around into categories, or even start over. The downside is that, as the researcher, you have to manually document each category.

Besides asking questions, the moderator might also ask participants to express their thought process aloud as they go, to gain further insights. You might therefore opt for a moderated session when you want to gain a deep understanding of how your audience thinks.

Unmoderated and remote card sorting

An unmoderated card sorting session involves participants working on their own and without a moderator. They’re usually run remotely online using a digital card sorting tool, where participants can drag-and-drop cards into groups.

Remote unmoderated card sorts require fewer resources, so are generally quicker, easier, and less expensive to organize than an in-person moderated session. One benefit of using a card sorting tool is that it analyzes the results for you, so you can see at a glance which items are commonly grouped together, along with the most common category names.

While you don’t have the benefit of asking participants to explain their thought process, most online tools have the functionality to ask participants follow-up questions.

You might run an unmoderated remote card sort when you:

• Are working with limited resources and budget.

• Want to gain insights from a large group of participants.

• Want to gain insights from participants with different demographics, e.g. from people in different countries.

Results from an unmoderated remote card sort test in Lyssna.

How to choose a card sorting method

When figuring out which card sorting method to use, it’s worth considering what stage your project is at. If you’re in the early concept stages of a website build, open card sorting might be beneficial. Closed card sorting might be the way to go if you’re further along and want to validate a concept.

Open and closed card sorts can also complement each other. For example, you can use an open card sort to define candidate sets of categories and follow this with a closed card sort to identify which set of categories performs best.

Resources, your research goals, and the specifics of your project will no doubt also affect your decision.