--- title: "Tree Testing" url: "https://www.insideuxdesign.com/en/glossar/tree-testing" language: "en" description: "What is tree testing? A plain-language guide with an example and tips. Learn how to check whether people can find content in your menu before you design it." published: "2026-10-14T09:50:32+02:00" updated: "2026-10-14T13:02:14+02:00" --- # Tree Testing Tree testing is a research method for checking whether people can find content in a navigation structure. Only the outline of labels is tested, with no visual design at all. - **Buchstabe:** T UX glossary # Tree Testing Tree testing is a research method for checking whether people can find content in a navigation structure. Only the outline of labels is tested, with no visual design at all. Imagine an online store for outdoor gear that has just designed a new menu. It looks tidy, and everyone on the team thinks it makes sense. But the question that really matters is a different one: Can a first-time visitor find the returns page, the size chart for hiking boots or the gift card for the family? That’s exactly what a tree test checks, before a single screen has been designed. ## Explained simply Tree testing is a research method for checking whether people can find content in a navigation structure. The “tree” is simply the outline of your website: main categories, subcategories and the individual pages beneath them, with no colors, images or layout. Participants get tasks and click through this text-only hierarchy until they think they’ve reached the right place. Here’s an everyday comparison: you’re standing in a hardware store where every shelf is empty and only the aisle signs are left. Can you find the aisle with the wall plugs from the signs alone? If not, the problem lies with the signs and the way things are organized, not with the products. The method used to be run on paper with index cards. Donna Spencer described it in 2003 as “card-based classification evaluation”. It is sometimes also called “reverse card sorting”, because it works the opposite way to [card sorting](https://www.insideuxdesign.com/en/glossar/card-sorting): a card sort generates a structure, a tree test evaluates one. ## What you measure The key metrics are the **success rate** (how many people end up in the right place?), **directness** (how many get there without detours or backtracking?) and **time** per task. The first click is especially revealing. According to the Nielsen Norman Group, it often predicts whether someone will complete the task. If first clicks are spread across several top-level categories, those categories probably overlap too much. ## An example Back to the outdoor store. Before, returns are tucked away under “My account” and the size chart under “Service”. In a tree test with the task “Your new hiking boots are too small. Where do you start an exchange?”, many people look under “Help” or go straight to “Footwear”. Only a small share find the right spot. The team renames “Service” to “Help and returns”, adds a link to the size chart in every footwear category and tests again. Afterwards, far more participants find the right path on the first try. ## Common misconceptions A tree test is not a full [usability test](https://www.insideuxdesign.com/en/glossar/usability-testing). Because search, images and page context are missing, it only shows how well the structure and labels work on their own. On the finished website, results may turn out better or worse. That’s not a flaw, it’s the point: it tells you whether a problem lies in the [information architecture](https://www.insideuxdesign.com/en/glossar/information-architecture) or in the visual design. For more on how to structure menus, read [Flat vs. Deep Hierarchy: Which Structure Is Best?](https://www.insideuxdesign.com/en/blog/flat-vs-deep-hierarchy-which-structure-is-best) ## In practice - **Don’t give away the answer.** Write tasks without the exact labels from your menu. Instead of “Find the returns page”, try “Your boots don’t fit. What do you do?”. - **Start with an easy task.** A simple warm-up task helps people get going and shows you who isn’t paying attention. - **Compare versions fairly.** When you test two structures against each other, use the same tasks with separate groups. For reliable differences, the Nielsen Norman Group says you typically need 50 or more participants per tree. ## Related terms [Card Sorting](https://www.insideuxdesign.com/en/glossar/card-sorting), [Information Architecture](https://www.insideuxdesign.com/en/glossar/information-architecture), [Usability Testing](https://www.insideuxdesign.com/en/glossar/usability-testing), [Mental Model](https://www.insideuxdesign.com/en/glossar/mental-model) ## Sources - [Page Laubheimer: Tree Testing: Evaluate Menu Labels and Categories. Nielsen Norman Group, 2023](https://www.nngroup.com/articles/tree-testing/) - [Page Laubheimer: Tree Testing Part 2: Interpreting the Results. Nielsen Norman Group, 2024](https://www.nngroup.com/articles/interpreting-tree-test-results/) - [Donna Spencer: Card-Based Classification Evaluation. Boxes and Arrows, 2003](https://boxesandarrows.com/card-based-classification-evaluation/) ## More terms [ ### A/B Testing An A/B test is an experiment that shows two versions of a page or element at the same time to randomly split groups of visitors. It lets you decide with real data which version works better. ](https://www.insideuxdesign.com/en/glossar/a-b-testing) [ ### ARIA ARIA is a W3C standard that adds roles, states and properties to HTML. It tells screen readers what an element is and how it currently behaves. ](https://www.insideuxdesign.com/en/glossar/aria) [ ### Accessibility Accessibility means designing websites, apps and digital documents so that everyone can use them, including people with visual, hearing, motor or cognitive disabilities. ](https://www.insideuxdesign.com/en/glossar/accessibility) [ ### Affordance An affordance describes what action an object makes possible and whether people can recognize it: a button invites you to press it, a handle invites you to pull. ](https://www.insideuxdesign.com/en/glossar/affordance) [ ### Alt Text Alt text is a short text version of an image, stored in the HTML alt attribute. Screen readers read it aloud so people who can’t see the image get the same information. ](https://www.insideuxdesign.com/en/glossar/alt-text) [ ### Atomic Design Atomic Design is a method for building user interfaces from small, reusable building blocks, from single elements like buttons all the way up to complete pages. ](https://www.insideuxdesign.com/en/glossar/atomic-design) [ ### BFSG The BFSG, Germany’s Accessibility Strengthening Act, has required many companies since 28 June 2025 to make certain products and digital services, such as online shops, accessible. ](https://www.insideuxdesign.com/en/glossar/bfsg) [ ### Card Sorting Card sorting is a research method in which people sort terms written on cards into groups. It shows you how they mentally organize content, so you can plan navigation that makes sense to them. ](https://www.insideuxdesign.com/en/glossar/card-sorting) [ ### Cognitive Load Cognitive load is the mental effort it takes to understand and use an interface. The less unnecessary thinking a design demands, the easier the actual task becomes. ](https://www.insideuxdesign.com/en/glossar/cognitive-load) [ ### Color Vision Deficiency A color vision deficiency means someone has a harder time telling certain colors apart than most people. The most common type is red-green deficiency. ](https://www.insideuxdesign.com/en/glossar/color-vision-deficiency) [ ### Contextual Inquiry Contextual inquiry is a research method where you observe and interview people in their real work environment. It shows you how they actually get tasks done, not just how they describe it. ](https://www.insideuxdesign.com/en/glossar/contextual-inquiry) [ ### Contrast Ratio The contrast ratio describes how much two colors differ in brightness, such as text and background. WCAG requires at least 4.5:1 for normal text. ](https://www.insideuxdesign.com/en/glossar/contrast-ratio)