Usability Heuristics & Evaluation

The durable, attributed laws of usable interfaces. These are not opinions — they are field-tested principles from Jakob Nielsen, Don Norman, Ben Shneiderman, and Dieter Rams. Use this skill to design screens that don't need explaining, and to evaluate any UI (web, mobile, desktop, TV, voice) against a shared, defensible standard.

How to use: design against the heuristics; evaluate with the method in §5. When you flag a problem, name the heuristic it violates and rate its severity — that turns a subjective "I don't like this" into a prioritized, fixable finding.

1. Jakob Nielsen's 10 Usability Heuristics

Published by Jakob Nielsen in 1994 (refined from a 1990 factor analysis with Rolf Molich), now maintained by Nielsen Norman Group (NN/g). They are "heuristics" — broad rules of thumb, not narrow guidelines — because they apply across every interface ever built. Memorize them.

H1 — Visibility of system status

Principle. The system should always keep users informed about what is going on, through appropriate feedback within reasonable time. Why it matters. Reduces uncertainty. Users build trust when the system communicates; they abandon and double-click when it goes silent. Follows it. A file-upload bar showing "3 of 8 files · 1.2 MB/s · ~12s left." A "Saved" indicator the instant autosave fires. A map app pulsing while it acquires GPS. A button that swaps to a spinner + "Submitting…" on tap. Violation. Tap "Pay" → the screen freezes with no spinner, no disabled state. The user taps again and gets charged twice. Fix. Disable the button on first tap, swap the label to a loading state, and confirm completion ("Payment received") or failure explicitly.