--- title: "Usability Testing" url: "https://www.insideuxdesign.com/en/glossar/usability-testing" language: "en" description: "What is usability testing? A plain-language explanation with an example, test types and practical tips. Learn how to find real problems with just a few people." published: "2026-10-14T09:50:32+02:00" updated: "2026-10-14T13:00:20+02:00" --- # Usability Testing In usability testing, real people complete typical tasks with a product while you watch where they hesitate or fail. It helps you find problems before they frustrate your customers. - **Buchstabe:** U UX glossary # Usability Testing In usability testing, real people complete typical tasks with a product while you watch where they hesitate or fail. It helps you find problems before they frustrate your customers. Imagine a gym launching a new app that lets members book classes. Inside the team, everything works smoothly, since everyone knows every button by heart. Then the team sits a woman in her early sixties down with the app and asks her to book a yoga class on Thursday. Two minutes later, she’s still searching. Usability testing is how you catch moments like this. ## Explained simply In usability testing, you ask people to complete typical tasks with a product and watch what happens. Usability describes how easily, efficiently and satisfyingly something can be used. You’re testing the product, not the person. Think of it like writing directions to your home and handing them to a friend who has never been there. Wherever they take a wrong turn, your directions are unclear. In the same way, a usability test shows you where an interface leads people astray. ## How a test works According to the Nielsen Norman Group, every test has three core elements: a facilitator who runs the session, realistic tasks and participants who resemble your actual audience. Participants are often asked to think aloud, saying what goes through their mind as they work. That way you learn not just *where* they get stuck, but *why*. Tests can run in person or remotely, moderated or unmoderated. In unmoderated tests, participants work alone with an online tool such as [Maze](https://www.insideuxdesign.com/en/ressourcen/maze), which presents the tasks and records the screen. There’s also a difference between qualitative tests, which uncover problems, and quantitative tests, which measure metrics like success rate or time on task. ## An example Back to the gym app. Before: the class schedule hides behind an unlabeled icon, and most bookings still happen by phone at the front desk. The team tests with five members, and four of them look for the schedule in the wrong menu. After: the section is now simply called “Book a class” and sits prominently on the home screen. In a second round, every participant finds the yoga class within seconds. ## Common misconceptions You’ll often hear that five participants are always enough. That’s only partly true. Jakob Nielsen showed that five people in a qualitative test will find around 85 percent of the problems on paper, assuming a single person uncovers about 31 percent. That’s why he recommends several small rounds instead of one big one. If you have very different user groups or want to measure metrics, you need more participants. To learn how to turn your observations into concrete improvements, read [How to Extract Valuable Feedback from Usability Tests](https://www.insideuxdesign.com/en/blog/how-to-extract-valuable-feedback-from-usability-tests). ## In practice - **Write tasks without hints.** Say “Book a yoga class on Thursday,” not “Click on Schedule.” Otherwise, labels from the interface give away the answer. - **Don’t help, even when it’s hard.** Every bit of help skews the result. Ask a question instead: “What did you expect to happen here?” - **Test small and often.** Three rounds with five people each tell you more than one round with fifteen, because you can fix things in between. ## Related terms [User Research](https://www.insideuxdesign.com/en/glossar/user-research), [Prototype](https://www.insideuxdesign.com/en/glossar/prototype), [System Usability Scale](https://www.insideuxdesign.com/en/glossar/system-usability-scale), [Heuristic Evaluation](https://www.insideuxdesign.com/en/glossar/heuristic-evaluation) ## Sources - [Kate Moran: Usability (User) Testing 101. Nielsen Norman Group, 2019](https://www.nngroup.com/articles/usability-testing-101/) - [Jakob Nielsen: Why You Only Need to Test with 5 Users. Nielsen Norman Group, 2000](https://www.nngroup.com/articles/why-you-only-need-to-test-with-5-users/) ## 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)