What is usability testing and how would you run a simple one?

What the interviewer wants to hear

• Watching real users try to complete realistic tasks
• Recruit participants who match the target users
• Use a script with tasks, ask them to think aloud, avoid leading
• Record issues and severity, share findings and fix

Model answer

Usability testing means watching real people try to complete realistic tasks with a design, so we can see where they struggle. For a simple test, I first write the goals and three to five tasks, such as finding a product and paying for it. I recruit around five participants who match our target users. In each session I explain that we are testing the design, not them, and ask them to think aloud. I give the tasks without hints and use neutral prompts like what are you expecting here. I note where they hesitate, make errors or give up. After the sessions I group the issues, rate them by severity, and share short findings with clips. Then the team fixes the top problems and, if possible, we test again.

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• Walk me through your design process.
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