Tree testing in UX: Complete guide

What is tree testing?

Tree testing is a UX research method that looks into how users navigate through the structure of an interface, like menus, categories, or features, to find specific information or complete specific tasks. It involves presenting the testers with a simplified version of the application’s navigational paths (ie. a “tree”) without any visual design elements and testing how easily they can reach their goals or perform a given task. This helps identify issues in the structure or labelling that might confuse users or slow them down.

Its role in UX design

In design, this research method plays a vital role in shaping the user experience by ensuring that the key functions of your platform are easy to access. Whether you’re designing a SaaS platform with multiple tools or a mobile app with intricate workflows, tree testing allows you to see where users might struggle to navigate through the system. By using this method early in the design process, teams can optimise the structure to align with user expectations, making it more intuitive and efficient to use.

The tree-testing process

Setting up your tree test

To set up a tree test, the first step is to develop a clear understanding of your application’s architecture. Strip back all of its visual elements and focus solely on the information hierarchy. The aim is to create a “bare bones” tree structure where users can navigate through the different levels of categories and subcategories. Tools like Treejack from Optimal Workshop can help set up these trees quickly and offer a platform where users interact with the structure remotely.

The goal is to simulate real-world navigation and gather insights without the distractions of busy design elements. Make sure that the tree reflects your application’s core navigation paths, such as product categories or service flows and always test the full depth of the structure, not just individual sections. This gives a more comprehensive view of how intuitive the overall experience is.

Developing and refining tasks

Coming up with the right tasks for participants is crucial to getting the most useful feedback possible from a tree test. The tasks you set should be goal-oriented and reflect real-life scenarios that one of your users would expect to experience while using the application in a normal setting. For example, if you were running a tree test for a project management app, a task could be, “Find where to assign a task to a colleague.”

Try to make these tasks as neutral as possible so that you don’t lead users towards a specific answer, but also make them clear enough so that the user knows exactly what action to take. Tuning the wording after pilot testing is important to minimise any ambiguity. The better aligned your tasks are with the application’s intended use, the better the insights you’ll gather about the user journey and where issues may arise.

Participant recruitment

Recruiting the right participants for your test is key to ensuring that the results reflect the experiences of actual users. Ideally, participants should be representative of your application’s target audience. If your product is used by a variety of groups, aim to recruit a balanced mix to gain actionable insights across all perspectives.Typically, a small sample size of around 5 to 15 users is sufficient for tree testing as it quickly reveals patterns in navigation failure or success. While you don’t need large numbers for meaningful insights, make sure participants have enough familiarity with similar applications to provide relevant feedback.

You can recruit participants via user research platforms such as UserTesting, Lookback, or Optimal Workshop, depending on your resources, or post on social media/mailing lists to find the right audience.
Alternatively, we offer a participant recruitment service as a valuable resource to enhance your project outcomes. Our team will work closely with you to identify the target audience that aligns with your research or project objectives. Using a combination of demographic, behavioural, and attitudinal criteria, we can design a recruitment brief that will clearly define the scope as well as help recruit a representative audience.

Conducting tree testing

Methodology

The method for tree testing is straightforward, but it requires some planning to ensure accurate results. To start, you’ll present your participants with the stripped-back version of your app’s structure that you created as part of your preparation – the ‘tree’.

Participants are then given their tree-test tasks, such as locating a specific feature or completing a certain action, using only the tree to navigate. The goal is to see whether they can find their way to the correct destination without any visual design cues.

This can be done remotely, using some of the online tools mentioned earlier (like Optimal Workshop or Maze.) These tree testing tools allow your participants to engage with the test on their own devices while enabling you to track and measure performance metrics like success rates, time taken to complete tasks, and any errors made during the process.

The simplicity of tree testing allows for quick, iterative cycles, helping you refine your application’s navigation based on real user behaviour. Just be sure to run a pilot test first, as this will help you fine-tune the wording of tasks and ensure the structure is properly set up.

Analysing results

Once your tree test is complete, it’s time to look into the data. Key metrics include the success rate (how many users successfully completed the tasks they were given), directness (whether they took a straight path to the destination), and time to completion. Any patterns of confusion, such as high rates of backtracking or abandonment, should be closely examined to identify areas for improvement.

Data from user research platforms like UserZoom or Lookback can be automatically compiled into reports, offering heatmaps or visualisations of user pathways and insight into task completion rates. For instance, you might see that a particular branch of your tree is consistently problematic for users, indicating that a rethink of its labelling or structure might be in order. It’s essential to complement these quantitative insights with qualitative feedback—such as comments from users about why they found a task difficult—to create a well-rounded understanding of your app’s navigation challenges. This combination of quantitative data and qualitative insights will help you prioritise changes and optimise the user experience.

Common tree testing mistakes

Tree testing is straightforward, but some common mistakes can impact the quality of your results. Here’s what to watch out for:

1. Poorly defined tasks

A frequent mistake is creating tasks that are vague or too complex. If your list of tasks doesn’t clearly reflect what users would do in real life, the results may not represent true navigation behaviour. Keep tasks simple, relevant, and easy to understand.

2. Testing an incomplete tree

Only testing part of the hierarchical structure limits your insights. You won’t spot broader issues if you only test a small section. Always test the full depth of your navigation to ensure you’re covering the complete user journey.

3. Ignoring user feedback

While data is essential, don’t overlook what participants say. Their comments on confusing paths or unclear labels provide valuable context. Combine both qualitative user feedback and data for a fuller picture of navigation issues.

4. Recruiting non-representative users

Testing with users who don’t match your product’s audience can lead to misleading results. People unfamiliar with similar apps may struggle more than your actual users. Always recruit participants who represent your target audience.

5. Skipping the pilot test

Skipping a pilot run can lead to flawed results. A pilot test helps you catch issues with tasks, labels, or the structure before the main test. It ensures the test runs smoothly and delivers reliable insights.

Benefits and limitations of tree testing

Benefits of tree testing

There are several advantages of tree testing in UX research, making it a valuable tool for evaluating navigation structures:

• Clarity in navigation: It helps identify if users can easily understand and use the hierarchy of information, revealing areas where the structure may need adjustment.
• Early problem detection: By testing the structure without design elements, you can spot potential issues before the final design is implemented, saving time and resources.
• User-centric insights: It provides direct feedback from users on how they interact with the structure, offering a deeper understanding of their mental models and preferences.
• Cost-effective: Tree testing is relatively inexpensive compared to full-scale usability tests, allowing for frequent testing throughout the design process.

Limitations of tree testing

Despite its benefits, tree testing does have some limitations:

• Limited scope: It focuses solely on the structure of navigation and does not account for visual design, interactive elements, or the overall user experience.
• Potential for misinterpretation: Results can sometimes be misinterpreted if tasks are not well-defined or if the test lacks real-world context.
• Not ideal for early stages: If the overall structure is not yet clear, tree testing might not provide useful insights and can be more effective once the structure is more developed.

Balancing these benefits and limitations ensures that tree testing is used effectively and in conjunction with other research methods to achieve comprehensive insights into user navigation.

Tree testing vs card sorting

Comparative overview

Tree testing and card sorting are both useful methods for evaluating and improving information architecture, so they’re often grouped together in the same discussion, but they do serve different purposes. On the one hand, tree testing focuses on assessing the effectiveness of an existing navigation structure. It evaluates how easily users can find information within a predefined hierarchy. Card sorting, however, is mostly used during the early stages of design to understand how users categorise and organise information. By having participants sort cards representing different items into groups that make sense to them, designers gain insights into user mental models and how to structure content before setting up their navigation structure.

Integrating tree testing with other UX methods

Combination strategies

Tree testing is a powerful tool on its own, but its effectiveness can be significantly enhanced when combined with other UX research methods. Here’s how to integrate tree testing with various approaches for a more comprehensive understanding of user experience:

• Card sorting: Use card sorting to gather insights on how users group information and label categories. This helps in structuring your tree test to reflect users’ mental models, ensuring that the navigation aligns with their expectations.
• Usability testing: After refining the navigation structure with tree testing, conduct usability testing with a prototype to observe how users interact with the complete interface. This allows you to validate if the improved structure translates well into a functional design.
• First-click testing: Combine tree testing with first-click testing to evaluate if users can successfully navigate to their desired information on their first attempt. This helps in understanding how intuitive the navigation structure is in practice.
• A/B testing: Implement different navigation structures and use A/B testing to compare their effectiveness. This helps determine which version performs better in terms of user efficiency and satisfaction.
• User surveys: Follow up tree testing with user surveys to gather qualitative feedback on the navigation experience. This can provide context to the quantitative data collected during tree tests and highlight areas for further improvement.

By integrating tree testing with these methods, you create a more robust research framework that covers both the structural and experiential aspects of user navigation, leading to a more refined and user-friendly design.

How tree testing impacts conversion rates in UX

Successful tree testing sessions have the potential to directly effect your conversion rates by streamlining the user journey. When users can navigate your application efficiently, they’re more likely to complete actions such as purchases or sign-ups. Simplified navigation reduces obstacles, making it easier for users to achieve their goals, and therefore, a higher task success rate.

Effective navigation ensures users can find what they need quickly, which keeps them engaged with your platform. When users encounter fewer barriers, their experience improves, and they are more likely to follow through with their intended actions.

Conversely, if users struggle to locate key features or information, they may abandon the process before conversion. Tree testing helps identify and rectify these issues early, ensuring users have a smooth path to complete their actions.

In essence, tree testing refines navigation to enhance the user journey, leading to higher conversion rates and a more successful application overall.

Final thoughts

Tree testing is a crucial method for refining navigation systems, ensuring users can easily find information and complete tasks. By integrating tree testing with other UX methods, such as card sorting and usability testing, designers can create more intuitive and user-friendly applications. This comprehensive approach helps address usability issues early, leading to a smoother user experience and a more effective product.