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, 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.
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, Prototype, System Usability Scale, Heuristic Evaluation