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Card Sorting: Your Guide to Uncovering Mental Models & Informing UX Decisions

Card sorting enables you to discover how people understand information, how they feel about different ideas, and helps designers structure the information of a site or product. Throughout this guide, we’ll explore the benefits of different kinds of card sorting, how to run a successful card sort, and which tools to use. Anchored in advice from UX design and research experts, stick with this guide to go from novice to pro in your card sorting skills.

Try card sorting with Maze

Use Maze to run card sorting sessions and discover how users understand and categorize information.

Chapter 1

What is card sorting? Improving information architecture and understanding your user

Card sorting is a UX research method that helps you discover how people understand and categorize information.

In a card sort—sometimes called a card sorting study—participants group ideas or information written on cards into different categories in a way that makes sense to them. To conduct a card sort, you can use actual cards, pieces of paper, or an online card sorting tool.

There are many use cases for card sorting as a research method. Some of the most common ways researchers and designers use the insights from a card sort is to:

  • Create the information architecture (IA) of a website or homepage that is easy to navigate
  • Learn how people understand different concepts or ideas, and how they feel about them
  • Understand where users expect certain content to be found
  • Get inspiration for labeling and grouping content or ideas

Card sorting is such a valuable research tool, because it allows you to better understand people’s mental models and inform your information architecture, taking into account how the people who will use your product actually think.

Anca Croitoru, UX Researcher at New Relic

In this guide, we’ll discuss each of these use cases, but we’ll be focusing particularly on how you can use card sorting to design an intuitive IA.

The benefits of card sorting

Card sorting has many benefits within UX research and design, namely due to its ability to comprehensively understand a user’s way of thinking. It’s a powerful tool to grasp how users categorize information and determine the best way to organize and label the content on your website or product.

When working on information architecture, it’s important to match your users’ mental models, aka, the way they structure the content in their minds.

Guillermo Gineste, Senior Product Designer at Maze

Let’s get into more detail about a few of the main benefits of card sorting.

Discover user mental models

A mental model refers to the explanation of someone’s thought process about how something should work and their expectations, based on past interactions with other products.

One of the main benefits of card sorting is that it allows you to make informed decisions based on users' expectations and mental models rather than based on assumptions.

Understanding your users’ mental models can then in turn inform a variety of decisions, including how to:

  • Sequence tasks in an activity
  • Structure databases
  • Organize navigational elements
  • Name features and interface elements
  • Group and provide settings

By using card sorting, you get to understand the user’s mental model or test if your existing mental model works as expected. Card sorting takes the guesswork out of it.

Guillermo Gineste, Senior Product Designer at Maze

Improve information architecture

Information architecture (IA) is how you organize, structure, and label your content so that users can easily navigate your product and find the information they need. Creating an IA that's easy to understand and intuitive is key to providing a good user experience. That's where card sorting comes in.

Often, the way information is organized in a product subconsciously ends up reflecting the internal organization of the Product team. Card sorting allows designers to understand how users would perceive the product, and structure it accordingly.

Anca Croitoru, UX Researcher at New Relic

Card sorting is an excellent way to understand how your users expect the information architecture of a website or product to be structured. By presenting participants with different elements of the product and allowing them to group items into what feels natural, you’re able to get a deep level of insight into how potential users approach navigating your product and expect information to be structured.

These insights will allow you to make informed decisions and organize your content in a way that makes sense to your audience.

Empathize with users

Card sorting provides you with a glimpse into the perspective of your user. You can learn how people understand different concepts or ideas, and how they feel about them.

Whether it’s a selection of potential features or different naming conventions, card sorting is the ideal method to gain feedback from users based on their first impressions and instincts.

The best products are created with their user’s needs and pain-points in mind. Card sorting can allow you to start understanding these early on, before too much time has been invested in ideas that don’t align with your users.

Gather naming and categorization ideas

Card sorting is an excellent way to gather new ideas from your target user base, from understanding naming conventions and colloquialisms to generating new categories or sub-groups.

By providing a group of potential users with the space and freedom to suggest ideas and categorize information in a way that makes sense to them, you are provided with a plethora of diverse thoughts and perspectives which are then yours to shape to your product.

Gain insights quickly and easily

Last but not least, card sorting is a simple and cost-effective method of gaining insights about your users and how they think. Tests are easy to arrange and provide fast, reliable results.

As we’ll explore in the next section of this guide, there are multiple ways to run a card sort—allowing you to easily connect with the users that will provide the most value for your research. You can run a card sort in person, using physical cards, or remotely using an online tool like Maze.

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Types of card sorting

💡 This section is supported by insights from Guillermo Gineste, Senior Product Designer at Maze.

Determining the right approach to your card sort is a key part of ensuring you get the results you’re looking for. When it comes to selecting the right type of card sorting, Vaida Pakulyte, UX Researcher and Designer at Electrolux, explains:

All card sorting types complement each other. Choosing the right type of card sorting comes down to the objective of your project.

Vaida Pakulyte, UX Researcher and Designer at Electrolux

In this section, we’ll look at the three main types of card sorting you can choose from:

  • Open card sorting
  • Closed card sorting
  • Hybrid card sorting
Type What it is Good for
Open card sorting Participants sort the cards into groups then name the groups themselves. • Creating new information architectures or improving existing ones
Finding patterns in how users expect to find content
Generating ideas for how to structure and label your website or app information
Closed card sorting A moderator gives participants predefined categories to sort the cards into. Finding out if users understand your categorizations
Pinpointing misleading categories and make informed decisions on how to improve
Ensuring information is organized in a way that makes sense to your audience.
Learning how users prioritize and rank information within existing categories
Hybrid card sorting Some categories have already been defined for participants to sort the cards into, but participants also can create their own categories. Testing existing IA and website structures to see if they work as expected
When you have some information categorized, but need input for organizing the remainder
If flexibility is a priority: you can give category examples to participants, while allowing them to add their own

Depending on your objectives, you can then also choose from different card sorting formats:

  • Moderated vs. unmoderated card sorting: A researcher can conduct and oversee the session (moderated), or users work through the session on their own (unmoderated)
  • Paper vs. digital card sorting: You can either write the topics on physical index cards (paper) or type them onto cards in a simulated environment (digital)

Of course, as with any UX research, each method has its ideal circumstances, and its pros and cons. Let’s take a look.

Open card sorting

Open card sorting is a generative research exercise, rather than an evaluative one—meaning, it helps uncover and define the problem at hand, rather than evaluating a solution.

In this card sorting type, participants organize topics into categories that make sense to them and then create their own names for these categories.

The strength of an open card sort is in generating ideas and finding consensus amongst large numbers of people.

Guillermo Gineste, Senior Product Designer at Maze

This method helps reveal not only how users classify the cards but also what labels they use for each group, which generates new ideas and category names, and provides a deeper understanding of your user.

Vaida Pakulyte, UX Researcher and Designer at Electrolux, notes that “An open sort exercise is good at the beginning of the project because it helps you to understand how people naturally categorize information.”

If you're unsure how to organize your website or app information, an open card sort can help. The results from an open card sorting test are helpful in understanding how a target audience structures information, identifies potential bottlenecks, and can help to better label categories and sub-categories.

What is open card sorting good for?

In particular, open card sorts are commonly used to:

  • Create new information architectures or improving existing ones
  • Find patterns in how users expect to find content
  • Generate ideas for how to structure and label your website or app information architecture

Closed card sorting

Closed card sorting is an evaluative research method—it’s used to assess and validate potential ideas or solutions. In a closed card sorting session, you present participants with a pre-selected set of categories and ask them to prioritize and sort cards as it makes sense to them, within those defined categories.

This type of card sorting doesn't reveal how users naturally categorize a set of topics. Instead, it's usually used to test if existing category labels are clear. Guillermo suggests that: “Closed card sorting is ideal for testing existing information architecture, as you’ll only get the information you specifically need, so it’s really efficient.”

What is closed card sorting good for?

Closed card sorting is a great way to test an existing structure, validate decisions when adding new items to an existing system, reorganize or rank content. You can use this method to:

  • Find out if users understand your categorizations
  • Pinpoint misleading categories and make informed decisions on how to improve
  • Ensure information is organized in a way that makes sense to your audience.
  • Learn how users prioritize and rank information within existing categories

Tip ✨

You can also use a closed card sort as a follow-up to an open card sort to analyze if the categories identified in the first round seem logical to most users.

Hybrid card sorting

Hybrid card sorting is a type of card sorting that combines open and closed card sorting methods. Participants can group a set of cards into predefined categories, but they can also create new categories.

This technique is ideal for when you already have certain categories established, but you need input into how the remaining ones should be labeled, or aren’t positive on what goes where.

I use hybrid card sorting to map all the content of the website. First, I ask users and stakeholders to group the content into categories, and then I get the participants to name or create their own categories.

Vaida Pakulyte, UX Researcher and Designer at Electrolux

When improving a live website, the hybrid method might be most suitable. First, you can conduct a hybrid card sorting exercise to see how participants label and sort your website’s structure. You can then follow that up with a closed card sorting session that will help you validate the website’s structure and test if people can find the relevant information. Vaida explains: “Once the initial structure is set, then you can test it a second time with closed card sorting or a tree testing exercise.”

What is hybrid card sorting good for?

Hybrid card sorting is a great format if you’re looking to validate existing ideas and information, without closing off the potential for new ideas. It’s particularly useful if:

  • You want to test existing IA and website structures to see if they work as expected
  • You have some information categorized, but need input for organizing the remainder
  • The topic you’re researching is particularly complicated, as you can provide examples of categorization

Moderated card sorting

Moderated card sorting involves a moderator who will debrief the participants and ask them follow-up questions following the card sort. This helps give you qualitative insights to understand the rationale behind the grouping.

Moderated card sorting is best for when you want quality over quantity. It may take longer, but you can gain deeper understanding by speaking directly with participants to learn their reasoning.

Guillermo Gineste, Senior Product Designer at Maze

Like all card sorting, moderated card sorts can be conducted with paper card sorting, or remotely using an online tool. However due to the nature of involving a facilitator, most commonly they’re conducted in person. Moderated card sorting often happens in the form of a one-to-one study, which allows the moderator to directly ask follow-up questions, or even ask the participant to express their thought process aloud while sorting.

When deciding the format of your card sorting study, determining between moderated or unmoderated is an important step. Moderated card sorting often lends itself to situations where you want to:

  • Gain a deep, nuanced understanding of the user, rather than a wide breadth of knowledge of a group
  • Understand the direct thought-processes of users, rather than just the outcomes

Unmoderated card sorting

Unlike moderated card sorts, unmoderated card sorting requires participants to organize content into groups on their own, either as a solo activity or multiple users working together.

These sessions can be quicker and easier to organize as they don’t require facilitators, and you can use online card sorting tools such as Maze to conduct remote card tests and collect insights.

I find unmoderated card sorting is best when you want to see results from a large number of users, for example how an existing IA works through closed card sorting, or you want to get as many ideas possible through open card sorting.

Guillermo Gineste, Senior Product Designer at Maze

Running your card sort as an unmoderated study gives participants the freedom and flexibility to do what feels right, without feeling as though they are being watched, which could make them reconsider their natural decisions.

Unmoderated card sorting is the format to go with if you’re looking to:

  • Get large amounts of feedback from multiple users, or multiple groups of users
  • Conduct a card sort within a limited budget
  • Uncover the most natural responses from users, and you don’t mind interpreting that data yourself (rather than speaking directly with participants)

Digital card sorting

In digital card sorting, you use online card sorting tools and card sorting software to simulate the card sorting drag-and-drop activity of dividing cards into groups.

This method is generally easier because it requires less resources, and the tool will do the heavy lifting of analyzing the results and revealing which items were most commonly grouped. It’s also much faster because you can get a sufficient amount of data in less time and identify patterns quicker.

Due to the availability of developed online tools, digital card sorting can work well for open or closed card sorts, as well as moderated or unmoderated. When deciding between digital or paper/in-person card sorting, it often simply comes down to resource availability and location.

Digital card sorting works especially well if you are:

  • Looking to gain insight from a wide variety of participants, e.g. people from multiple countries
  • Under time constraints and need to conduct the card sort quickly and process results quickly

Paper card sorting

Paper or in-person card sorting is a more traditional technique, where you write down the topics on physical cards and ask participants to group them on a large workspace. This format naturally lends itself more towards moderated card sorting, but can also be conducted as unmoderated.

Guillermo Gineste, Senior Product Designer at Maze, suggests today there is little difference between digital and paper card sorting techniques. “The main advantage of in-person card sorts is that it allows for more complex groups (e.g. groupings within groupings). Apart from that, there aren’t many advantages versus using a digital tool; the data will look similar and you are able to ask the same questions.”

While paper card sorting is very flexible, with the availability of many intuitive and extensive online tools, it doesn’t offer much which cannot be accomplished through a digital card sort.

Ultimately, identifying the card sorting type that’s best for you comes down to the type of project you’re conducting, your user research goals, and available resources.

Moving forward

In conclusion, card sorting is an excellent way to get ideas, gain feedback from users and understand how they think, gather insight on potential IA and discover your users’ mental models.

Whether you prefer to work with physical index cards or online card sorting software, with a moderator or not, every card sort will answer a different set of questions and provide new understanding of your users, so you can lay a better foundation for a user-centered design.

Now we’ve discussed what options you have when it comes to card sorting, let’s take a look at just how you can plan and execute a successful card sort within UX research.

Frequently asked questions about card sorting

What is card sorting used for?

Card sorting (also called UX card sorting) is a UX research method that helps you discover how people understand and categorize information.

Is card sorting qualitative or quantitative?

Card sorting can be a quantitative or qualitative research method.

Common goals when carrying out a card sorting study include: learning what users think about an existing IA, understanding why users group ideas in certain ways, and discovering how users categorize information.

These results could be qualitative, e.g. participant commentary during a moderated session, or they could be quantitative, e.g. statistics on time to complete the test, number of cards sorted, or percentage of cards in one group.

How long does a card sorting session take?

Generally, the time needed to complete a card sort will depend on several factors:

  • How many cards are used
  • How many users are participating, if working together
  • Whether the test is moderated
  • Whether you are collecting quantitative or qualitative data
  • Whether you are manually analyzing the data or have a tool to process this

Are there any disadvantages to card sorting?

As with all research methods, there are both advantages and disadvantages to card sorting. Some of the disadvantages include:

  • Unmoderated card sorting may not provide deep enough insights
  • Analyzing the results of a card sort (particularly a paper one) can be very time-consuming
  • Card sorting does not account for tasks at hand and wider context—for example, we may group tomatoes under ‘fruits’, however if the context was within a supermarket, they may be categorized under the ‘vegetable aisle’.

What are the main benefits of card sorting?

The main benefits of card sorting are that it enables researchers and designers to:

  • Discover users’ mental models
  • Empathize with users
  • Gain insights quickly
  • Gather new ideas
  • Improve information architecture