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.
nngroup.com
daily design digest
Get the weekly emailPublished 11 July 2026 · Source dated 29 December 2025
A controlled field experiment reported via UX Tigers found startups that redesigned their whole workflow around AI made 90% more revenue than peers who just used AI to speed up existing tasks. It's one study with a bold number, but the underlying pattern — rethink the process, don't just add a tool — is worth testing yourself.

Coach
Map your design process end-to-end and flag one step you'd redesign around AI, rather than just speed up with it.
Source: uxtigers.com ·
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.
nngroup.com
With AI tooling dominating design chatter, it's easy to forget the cheapest, fastest usability method still works: heuristic evaluation. It costs nothing but time and catches problems before you ever test with real users.
uxdesign.cc
Nielsen's usability heuristics remain a go-to lightweight method for catching obvious UX problems before user testing, decades after they were written. It's boring, reliable, and still worth learning properly.
interaction-design.org