Still true: 5 users find most of your usability problems

NN/g's classic finding — that testing with five users uncovers most usability issues — still holds and still gets ignored by teams who think they need a 'proper' sample size.

This is one of the most cited pieces of UX research and it's still the best argument against 'we don't have budget for research.' Testing with five users in a single round typically surfaces most of the big, obvious usability problems; more participants mostly gets you diminishing returns on the same issues. As a junior, this is your permission slip: you don't need a research team or 20 participants to validate a flow. Five honest, unscripted conversations with the right people beat zero testing every time. Calling this **established** — the finding is over two decades old and still underpins most lean UX research guidance today.

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