People who build a product know every button by heart. For that very reason, they struggle to see where a new user will get lost. Usability testing fixes that blind spot: you watch real people try to complete tasks and discover, in practice, what works and what confuses.
In this guide, we show how to plan, run and analyze a test, even on a tight budget.
What is usability testing
It is a research method in which participants who represent your target audience perform tasks in a product while a facilitator observes. The goal is to identify usability problems, such as confusing steps, ambiguous labels and frequent errors.
Remember: the test evaluates the product, not the participant. If someone cannot complete a task, the failure lies in the design.
Types of tests
- Moderated: a facilitator guides the session, in person or by video call, and can ask follow-up questions.
- Unmoderated: the participant completes tasks alone while a tool records the screen and voice.
- In-person or remote: remote is cheaper and reaches people anywhere; in-person lets you observe body language.
- Qualitative or quantitative: qualitative uncovers problems and reasons; quantitative measures success rates and time with larger samples.
How many participants you need
Research from the Nielsen Norman Group shows that five participants usually reveal most usability problems in a qualitative test. Therefore, running several small rounds and fixing issues between them is more effective than one large study.
How to run usability testing in 6 steps
1. Define your goals
Choose what you want to learn. For example: "can users complete a purchase without help?" or "does the new menu make reports easier to find?".
2. Recruit the right participants
Select people who represent your real audience. Avoid teammates, who already know the product.
3. Write realistic tasks
Create scenarios rather than instructions. Instead of "click Reports", try "you need to know how much you sold last month; how would you find out?". That way, you do not give away the answer.
4. Run the session
- Explain that you are testing the product, not the person.
- Ask the participant to think aloud.
- Avoid helping or leading. If they ask something, respond with "what would you do?".
- Record the session, with permission, so you can review it later.
5. Analyze the results
Gather your observations and group similar problems. Next, rate each one by severity: critical, when it blocks the task; serious, when it causes major difficulty; and minor, when it is merely annoying.
6. Prioritize and fix
Tackle critical problems in the tasks that matter most to the business first. Then test again to confirm the changes worked.
Useful metrics
- Success rate: the percentage of participants who complete the task.
- Time on task: how long completion takes.
- Errors: the number and type of mistakes made.
- SUS (System Usability Scale): a ten-question survey that produces a score from 0 to 100.
Tools
For prototypes, Figma lets you test clickable flows before writing code. For remote sessions, video calls with screen sharing work well. Platforms such as Maze and Lyssna make unmoderated tests easier, while session recording and heatmap tools complement analysis in production.
Frequently asked questions
When should I test?
At every stage. Testing prototypes is cheaper, but testing the live product reveals real-world usage problems.
Are usability testing and A/B testing the same?
No. Usability testing explains why people struggle. A/B testing measures which of two versions performs better with a large number of users.
Conclusion
Simple usability testing with five people uncovers problems that months of internal meetings never find. Define goals, write realistic tasks, observe without interfering and fix what matters most to the business. If you want to validate a system or prototype with real users, WDS Developer can run that process for you.
