Closed Card Sort

By Philip Burgess | UX Research Leader

Understanding how users organize information is key to creating clear and intuitive navigation and content structures. One effective method to gather this insight is the closed card sort. This technique helps designers and researchers test how well predefined categories work for users and identify potential improvements in labeling or grouping.

Person performing a closed card sort with labeled cards on a table

What is a Closed Card Sort?

A closed card sort is a user research method where participants sort a set of items into categories that are already defined by the researcher. Unlike open card sorting, where participants create their own groups, closed card sorting tests how well existing categories fit the users’ mental models.

This method is useful when you have a clear idea of the categories but want to validate if users understand and agree with them. It helps identify confusing labels, misplaced items, or gaps in the category structure.

When to Use Closed Card Sorting

Closed card sorting works best in these situations:

• You have predefined categories from previous research or business requirements.

• You want to test the clarity and effectiveness of category labels.

• You need to confirm if users can easily find and group items under existing headings.

• You want to compare how different user groups categorize the same items.

  
  

For example, an e-commerce site might have categories like "Men’s Clothing," "Women’s Clothing," and "Accessories." A closed card sort can reveal if users consistently place items like scarves or hats in the expected categories or if they find the labels unclear.

How to Conduct a Closed Card Sort

Follow these steps to run a closed card sort effectively:

1. Prepare the cards

   Create cards representing the items or content pieces you want sorted. Each card should have a clear, concise label.

   
   

2. Define the categories

   List the categories participants will use to sort the cards. Make sure these categories are well described and distinct.

   
   

3. Recruit participants

   Select users who represent your target audience. The number of participants can vary, but 15 to 30 is often enough to identify patterns.

   
   

4. Explain the task

   Tell participants they will sort cards into the predefined categories based on what makes the most sense to them.

   
   

5. Observe and record

   Watch how participants sort the cards and note any confusion or hesitation. Use software tools or physical cards depending on your setup.

   
   

6. Analyze the results

   Look for patterns in how cards were grouped. Identify cards frequently misplaced or categories that caused confusion.

   
   

Benefits of Closed Card Sorting

Closed card sorting offers several advantages:

• Validates existing categories

It confirms whether your current labels and groupings match user expectations.

• Improves navigation and labeling

Insights help refine category names and content placement, making it easier for users to find information.

• Saves time in design

Since categories are predefined, the process is quicker than open sorting and easier to analyze.

• Supports iterative design

You can repeat closed card sorts after changes to test improvements.

Limitations to Consider

While closed card sorting is valuable, it has some limitations:

• Less discovery of new categories

Users cannot create new groups, so you might miss alternative ways they think about the content.

• Potential bias

Predefined categories might influence how participants sort items, limiting creativity.

• Not suitable for early exploration

It works best when you already have a category structure to test, not when starting from scratch.

Practical Example of Closed Card Sorting

Imagine a library website redesign. The team has categories like "Fiction," "Non-fiction," "Children’s Books," and "Reference." They want to check if users place books in these categories as expected.

Participants receive cards with book titles or genres and sort them into the four categories. The results show most users agree on "Fiction" and "Children’s Books," but many place biographies under "Non-fiction" or "Reference," indicating confusion.

The team decides to rename "Reference" to "Research Materials" and add a new category for "Biographies." A follow-up closed card sort confirms the changes improve clarity.

Cards sorted into predefined categories during a closed card sort session

Tips for Successful Closed Card Sorting

• Use clear, simple labels for categories and cards.

• Keep the number of cards manageable, ideally between 30 and 60.

• Provide instructions that encourage participants to think about where items belong naturally.

• Combine closed card sorting with other methods like open card sorting or tree testing for a fuller picture.

• Use digital tools like OptimalSort or UXtweak for easier data collection and analysis.

  
  

Final Thoughts

Closed card sorting is a practical way to test and improve your content organization. It helps ensure your categories make sense to users and supports better navigation design. By carefully preparing your categories and analyzing user sorting behavior, you can create a structure that feels natural and clear.