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 15 July 2026 · Source dated 1 August 2025
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.

Coach
Run a 10-heuristic pass on one screen from your portfolio this week and note three fixes — it'll sharpen your critique skills for interviews.
Source: interaction-design.org ·
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 Norman Group's ongoing research keeps reinforcing that structured usability testing beats AI-generated assumptions about users. AI can speed up synthesis, but it can't replace watching real people struggle with your interface.
nngroup.com