Tree Testing

Imagine you’re planning a weekend getaway to a new city. Your search has led you to a local tourism website and you’re browsing around for things to do and places to stay. Using the website’s navigation system, you’re looking for specific content to help you plan your trip, such as restaurant recommendations, upcoming events, hotel deals, and neighborhood guides.

You find this information right where you expect it to be, located under relevant menu categories labeled “hotels,” “events,” and “activities.” Because the website is structured predictably and the navigation labels are clear and descriptive, you can easily locate all the information you need.

How do website designers ensure their websites achieve this level of usability? They test their navigation systems on real users.

Tree testing is a user experience (UX) research method to evaluate how easily users can find key resources and information on a website or app. This testing method focuses on the navigation tree (also called the sitemap), which represents the behind-the-scenes organizational structure of a website.¹

A website’s navigation tree is structured a lot like a literal tree. The homepage acts as the trunk, the main pages or menu categories (about, shop, contact, blog, etc.) are the large branches that connect directly to the trunk, and the individual pages of the website (individual product pages, blog articles, etc.) form the tree’s twigs and leaves.

You can get a sense of a website’s navigation tree when interacting with the menu bar at the top of the page. Typically, top-level menu items link to the site’s main pages or “parent” categories, with subcategories or individual “child” pages nested under these. The menu labels act as signposts, telling you where you can find specific content within the hierarchical structure of the website. Tree testing helps designers determine if these navigation labels make sense to users and if the website is organized logically and predictably.²

Tree testing essentially isolates the navigation tree so that it can be evaluated on its own. During tree testing, users are presented with a text-based version of the tree — with labels for each category and page. Users are given a specific task and then asked to navigate to the location in the tree where they would expect to locate content that would help them with this task.

If we were testing the tree in the above image, we may ask participants to look for information that would help them manage their healthcare costs. Participants would then click through the tree, starting with the top-level categories, until they reached the location where they would expect to find this information. In this case, we’re testing if “Insurance Providers” is in the most logical location in the tree. The results of this tree test would reveal how many people found the correct information, how long it took, how many different paths they took to get there, and whether they got lost along the way.