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Creating user-friendly digital products involves how well information is organized and presented. A well-structured website or app not only enhances usability but also keeps users engaged and satisfied. Among the various methods used in UX research, tree testing and card sorting are two techniques that UX professionals use to improve site's navigation and information architecture (IA).
While both methods play a crucial role in understanding how users perceive and navigate content, they serve different purposes and are applied at various stages of the design process. Understanding the strengths and limitations of each can make a significant difference in the effectiveness of your research.
In this article, we’ll dive into a comprehensive comparison of tree testing and card sorting. We’ll explore what each method entails, when to use them, and how they can complement each other to create user-friendly designs. Whether you’re refining an existing structure or building one from scratch, knowing which method to use—and when—will set your project up for success.
Setup card sorting and tree tests with Hubble
Test your information architecture with card sorting and tree testing in Hubble
What is tree testing?
Tree testing is a UX research method designed to assess how well users can navigate and find information within a site structure. Unlike traditional usability tests that involve visual elements or fully developed interfaces, tree testing focuses purely on the logical structure of the information hierarchy or the "tree" of your site.
Typically, tree test is a task-based method which involves participants to navigate a tree of information to locate certain key terms or information. It helps evaluate whether your users can efficiently navigate through the site's structure to locate specific products or piece of information without getting lost.
Examples:
- "Where would you find information about credit score changes and updates?"
- "Where would you locate information about privacy notice in the website?"
- "Find the contact information for customer support."
- "Imagine you want to apply for a job at a company. Find where you can view current job openings."
- "Locate the return policy to see how long you have to return an item after purchase."
Purpose of tree tests
The primary goal of a tree test is to assess how easily users can find specific information within a proposed site structure. By isolating the navigation paths from visual design, the text-only version of the structure is put to the test so that you can pinpoint potential issues in how content is organized and labeled.
Tree testing is particularly useful for identifying navigational roadblocks, understanding how users interpret category labels, and validating whether the site's structure aligns with user expectations.
What is card sorting?
Card sorting is a UX research technique used to understand how users naturally organize information. During a card sorting session, participants are tasked to assign individual items (cards) to categories that make sense to them.
The method provides insights into how users perceive and organize content, thereby informing decisions about navigation, content grouping, and information architecture.
Depending on your research goals, you can either run open or closed card sorting:
- Open card sorting: allows participants to label their own categories. In open card sort, participants are given a set of cards or topics, and are tasked to create own groups as it makes sense to them. It is preferred when you’re in early stages of design or information architecture (IA) development as it lets you understand users’ natural thought processes for grouping information. Without any predefined groups or categories, it can lead to new ideas into grouping and unbiased results.
- Example:
Sort the health-related topics into categories that make sense to you, and name the categories.- Nutrition Tips
- Workout Routines
- Mental Health Resources
- Healthy Recipes
- Yoga and Meditation
- Fitness Challenges
- Example:
- Closed card sort: provides participants with predefined categories into which they must sort the items. It is useful for validating existing information architecture or navigation structures, ensuring they align with users’ expectations. One downside of employing closed card sort is that it doesn’t mimic the natural way of users browsing information as they are first provided with topic items to fit into predetermined bins.
- Example:
Sort these customer support topics into the categories provided. - Categories:
- Account Management
- Technical Support
- Billing and Payments
- Product Information
- Example Cards:
- Reset Password
- Billing Issues
- Product Specifications
- Troubleshooting Connectivity Problems
- Updating Personal Information
- Refund Requests
- Example:
Purpose of card sorting
The primary goal of card sort is to gather insights into how users group and label content. This method is especially useful during the early stages of design when defining the structure of a website or app.
By understanding how users categorize information, designers can create navigation systems and site structure that align with how users expect to navigate the product, making it easier for users to find what they need.
Tree testing vs card sorting
Understanding the differences between tree testing vs card sorting is critical for anyone working to improve website or app usability. While both UX methods focus on organizing and validating information architecture, their strengths, and limitations differ significantly. A thorough comparison can help you decide which method to deploy.
Exploration vs. Validation
Card Sorting
Card sorting is primarily an exploratory method: Its main goal being to uncover how users naturally organize information based on their mental models. Participants are presented with various content items and asked to group them in ways that make sense to them.
Card sorting is typically employed early in the design stage, especially when a site or product is being developed from scratch or undergoing a significant redesign. The results of a card sort can help inform the creation of menus, labels, and overall structure by aligning with how users think about content.
Tree Tests
Tree test is typically used as a validation method to evaluate whether an existing or proposed navigation structure is effective. Instead of asking users how they would categorize items, tree test asks them to find specific pieces of information within a predefined structure (the "tree").
Tree testing provides direct feedback on whether users can locate relevant information efficiently based on the given navigation paths.
Tree test is typically used later in the design stage, once a draft of the information architecture is in place. The results help identify usability issues, like confusing categories or misplaced content, that might prevent users from finding what they need.
Generative vs. Evaluative
In a sense, card sorting is a generative exercise because it focuses on exploring how users naturally group and categorize content. Participants create or select categories, helping generate ideas for structuring information that align with their mental models.
In contrast, tree test, often referred to as reverse card sorting, is a searching task where users are given specific objectives and asked to find content within an existing structure. It evaluates how well users navigate a predefined hierarchy, validating whether the categories and paths allow users to locate information efficiently.
When to Use Card Sorting vs. Tree Tests
Use Cases of Card Sorting
Card Sorting is helpful when you are still exploring potential structures for your content. It helps ensure that the organization of content matches how users think. It is helpful when:
- You need to design an information architecture from scratch or are conducting a major overhaul of an existing website or structure.
- You want to gain insights into user mental models, particularly how they naturally group and label website content.
- You are not sure how to name categories or subcategories and want to gather user-generated labels.
- You want to explore different versions on how users interpret your content, revealing multiple approaches to organizing the information.
- You have a redesign project with an existing IA structure using closed card sorting to improve usability and navigation of your app.
Use Cases of Tree Tests
Tree Test should be used when you want to validate whether users can navigate an existing structure successfully. It's ideal for:
- Confirming that your navigation system supports users in finding specific content without confusion.
- Identifying points where users struggle or make errors, allowing for fine-tuning of the hierarchy or category labels.
- Tree testing whether users can complete specific tasks (like finding a product or locating a help article) within the site’s information architecture.
- Tree testing similar variations of information architecture to compare how participants interact with the navigation structure.
Pros and Cons of Card Sorting and Tree Tests
Card sorting is ideal for broad explorations, discovering user preferences and designing an information architecture that matches how users think. On the other hand, tree testing is effective for validating a navigation system to ensure that users can easily locate what they're looking for by focusing on task completion and path analysis.
Card Sorting Pros
- Insight into user thinking: Card sorting is highly effective for gaining a deep understanding of how users perceive and organize information. It helps you align your information architecture with their expectations.
- Flexible exploration: The open-ended nature of card sorting (especially in open card sorts) allows users to define their own categories, revealing how they conceptualize your content. This can lead to unexpected insights that shape your navigation system.
Limitations of Card Sorting
- Lack of real-world context: While card sorting helps you understand user preferences for categorizing information, it doesn’t necessarily reflect how they will interact with a live product. While card sorting is effective for helping you identify the mental model and information hierarchy, other design elements that could be affecting your product navigation is not being tested.
- Limited task-based insight: Card sorting doesn’t involve task-based scenarios. It focuses solely on how users categorize information without assessing how easily they can locate specific content within a structure. This means further validation, such as tree testing, is often needed to ensure usability.
Tree Testing Pros
- Objective validation: Tree testing offers quantitative data on user performance, such as task success rate, completion times, and the paths users take to find content. These metrics provide concrete evidence of how well your structure works.
- Focused on usability: Rather than exploring how users group content, tree testing focuses on real-world behavior, validating whether users can navigate through a predefined system effectively. This makes it especially useful for identifying bottlenecks in navigation.
- Detailed diagnostics: Detailed tree testing results reveal how your users interact with the product, showing specific areas where users get lost or take wrong turns, enabling designers to troubleshoot and make targeted improvements to navigation paths.
Limitations of Tree Tests
- Limited to predefined structures: Tree testing helps evaluate an existing or proposed hierarchy, but it doesn’t help generate new ideas or explore users' mental models. In tree testing, participants interact with structure that is already set in place.
Best Practices and Tips
Following best practices for each UX research method ensures that the insights you gain are reliable, actionable, and user-centered. Below are helpful tips to maximize the research output for the two methods:
1. Choose the right type of research methods
Depending on the stage of your product and learning objectives, you have to decide whether to use open or closed card sorting, a hybrid mix of both tree tests and card sorting. Use card sorting when you need to explore how users naturally group and categorize content, making it ideal during the early stages of designing or reorganizing your information architecture.
An open card sort is best when you want users to freely create their own categories, helping you understand their mental models. This is useful for early-stage exploration. However, a closed card sort is more appropriate when you have predefined labels and want to see if users can place items into the correct groups.
In contrast, tree testing work by validating an existing or proposed navigation structure, ensuring users can easily find specific content. This testing method is more suitable for later-stage testing to confirm usability.
2. Avoid jargons and ambiguous labels
Use clear, simple language for the card labels. Avoid technical terms, internal jargon, or ambiguous wording that might confuse participants or lead to inconsistent results. The language that your team speaks internally about your product may not necessarily the same for your daily users. Only use terms that make sense and are relevant to participants.
3. Keep the study simple and limit the number of items
Don’t overwhelm participants with too many cards. Typically, 30–60 items work well for card sorting. If you have a large set of content, consider breaking it down into smaller, more manageable sorts.
When running a tree test, you don't have to test the entire navigation structure. Unnecessarily complex and excessive layers of information can confuse the participants. Test areas only that are relevant are important to your goals. You may consider using a stripped-down version of your navigation structure while leaving out any additional elements to keep the study focused.
4. Ask a series of follow-up questions for rich insights
To gather rich qualitative data from card sorts and tree test, asking relevant follow-up questions is essential. Make sure to ask questions that clarify participants' thought process and identify potential areas that were confusing or unclear to them.
Asking open-ended questions and scenario-based questions, such as "if you were looking for [an information], how easy or difficult would it be?" can make the task more grounded to the actual use of context clues.
5. Triangulate data with qualitative data
When conducting data analysis from card sorting and tree testing, focus on identifying patterns and qualitative data. For card sorting, cluster the data to reveal items of same category and common groupings based on what made most sense to the users.
Content grouped logically will keep your users more engaged throughout the product usage. In tree testing, examine success rates, paths taken, and time on task to identify usability bottlenecks.
6. Combine methods for detailed results
To maximize the effectiveness of your research, it’s often a good idea to use both tree testing and card sorting at different design stages. Start with card sorting to understand how users think about and categorize your content. Once you’ve developed a proposed structure based on those insights, use tree testing to confirm that the structure works as intended.
How to Choose the Right Method for Your Project
Selecting between card sort and tree testing depends on the stage of your project, the goals you want to achieve, and the type of insights you need from your users.
By project stage
Early in the design process
If you're at the beginning of your project and need to explore how users perceive and group content, card sorting is the better choice. It helps define your existing information architecture by revealing users' mental models, which can guide the initial structure of your navigation.
Later in the design process
If your project is further along and you already have a proposed navigation structure or site hierarchy, tree testing is ideal for validation. It allows you to assess whether users can successfully complete tasks and find information within the established framework, ensuring the system works in real-world scenarios.
By learning objectives: Exploration vs. Validation
Exploration
If the goal is to discover how users naturally organize content or how they categorize information in ways that make sense to them, opt for card sorting. This method provides deep insights into user preferences, helping shape your content categorization from scratch or during a redesign.
Validation
If your goal is to test an existing or newly developed structure to ensure it supports users' ability to find information quickly and efficiently, choose tree testing. It offers concrete data on success rates, user paths, and usability issues, confirming whether your structure works as intended.
The Hybrid Approach
Using both methods can be beneficial. Start with card sorts to explore and build your information architecture based on user-generated categories. Once the structure is developed, follow up with tree testing to validate and refine the navigation system. This combined approach ensures that your design is user-centric from ideation to execution.
Tools and Resources
Utilizing the right card sorting and tree testing tools help streamline the research process, allowing you to run studies more efficiently. Especially with these types of tests, the usability of the online tool can affect how participants engage with your study.
- With online tools like Hubble, you can streamline your research by using both tree testing and card sorting, along with other UX research methods like usability testing, 5-second tests, and more. The drag-and-drop interface for card sorting is intuitive for both researchers and participants, allowing you to easily run open or closed card sorts based on your needs.
- Refer to our library of relevant templates and questions to kickstart your project, whether you’re conducting card sorting or tree testing.
- You can directly recruit participants from Hubble to get feedback from target audience. Collect data as quickly as 30 minutes, and results are transformed into digestible pieces as a quick summary.
Real examples of follow-up questions
Card Sorting
- Could you elaborate on how you grouped these particular items together?
- How easy or difficult was it to categorize the items?
- If any, what items did you find difficult to categorize? Why? If any, what items did you find easy to categorize? Why?
- If any, what category names were unclear or hard to define? Why?
- What made certain items seem like they could belong to multiple categories?
- What other approach of organizing these items did you consider during the activity?
- If any, what category or items were missing?
Tree Testing
- How did you determine which paths were most likely to lead you to the correct location?
- What aspects of the structure made it easier or harder for you to find what you were looking for?
- What challenges did you face while trying to locate [item]?
- How did you handle moments when you felt unsure about which path to take?
- How well did the structure align with your expectations or mental model of the information?
- What other paths or options did you consider before making your final selection?
- How do you think the tree structure could be adjusted to better match your thought process?
- What surprised you during the navigation task, and how did that impact your choice?
These list of questions are all available in Hubble's study builder via the Question Bank.
Incorporating card sort and tree tests into your UX research method toolset will become handy. Card sort serves as a powerful generative exercise that helps define how users categorize and group information, laying a strong foundation for your information architecture. On the other hand, tree testing provides valuable validation of an existing structure, ensuring that users can easily navigate and locate the content they need.
By understanding the distinct purposes of each method and employing best practices for implementation, you can gain rich insights into user behavior and how you can better organize your information architecture.
Utilizing the right study design and resources enhances the efficiency of your research, while asking relevant follow-up questions will yield qualitative insights that further refine your approach.
Setup card sorting and tree tests with Hubble
Test your information architecture with card sorting and tree testing in Hubble
