Five usability tests often beat one focus group.
Focus groups are useful for attitudes. Usability tests are useful for watching somebody fail to use the thing you made. Those are not interchangeable jobs.
People are good at explaining what they think they would do. They are less good at predicting what they will do when a form asks for something unclear, a button is missing or a checkout flow changes order.
That is why focus groups and usability tests answer different questions.
Opinions are not behaviour
A focus group can help explore language, perceptions and early reactions to a category. It is a poor substitute for watching someone use an interface. Group dynamics encourage polite agreement and confident opinions. Neither tells you where a real user gets stuck.
Test a task, not a concept
In a usability test, give someone a realistic task and stay quiet. Ask them to book the room, find the invoice or change the delivery address. Watch what they click, what they miss and where they hesitate.
Nielsen Norman Group’s long-standing guidance is to test small groups repeatedly rather than wait for one large study. Five people is not a magic number or a legal requirement. It is often enough to reveal the obvious problems, then make time for a second round after fixing them.
The useful question is not “do users like it?” It is “can they finish the task?”
Keep the loop short
Recruit people who resemble the intended users. Test the same critical tasks. Fix the recurring failures. Test again. A small cycle run early beats a beautifully moderated conversation after the build is already committed.
