According to Jacob Nielsen’s research on usability testing, conducting usability testing on even a small number of users can uncover a great number of your usability problems. A single user will often uncover 33% of the problems, three users 66%, and five users 80%. To get about 100%, Nielsen recommends 15. Even if you cannot test 15, it is surely worth it to test a few or even one. Get out there and test.

For more information see:

From Screen Space 12: Usability & Usability Testing 101 Part 2—Selecting Users

Reference: Jacob Nielsen, “Why You Only Need to Test with 5 Users.”

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