ux-heuristic

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Conduct heuristic evaluation of user interfaces using Nielsen's 10 usability principles. Use this skill when the user needs to audit a website, app, or interface for usability issues, prioritize UX improvements, or conduct a quick expert review without user testing — even if they say 'review this UI', 'find usability problems', or 'why do users struggle with our app'.

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npx skill4agent add asgard-ai-platform/skills ux-heuristic

Heuristic Evaluation (Nielsen's 10 Principles)

Overview

Heuristic evaluation is an expert review method that assesses a user interface against established usability principles. It's fast (2-4 hours), cheap (no user recruitment), and finds 40-60% of usability issues. Use it as a complement to, not replacement for, user testing.

Framework

IRON LAW: Every Violation Gets a Severity Rating

Finding a violation is half the work. Rating its severity is the other half.
A cosmetic inconsistency and a critical workflow blocker are both "violations"
but require completely different response urgency.

0 = Not a usability problem
1 = Cosmetic only — fix if time permits
2 = Minor — low priority
3 = Major — important to fix, high priority
4 = Catastrophe — must fix before release

Nielsen's 10 Heuristics

#HeuristicQuestion to Ask
1Visibility of system statusDoes the user always know what's happening? (loading indicators, progress bars, confirmations)
2Match between system and real worldDoes it use the user's language, not system jargon? Are conventions familiar?
3User control and freedomCan users undo, redo, go back, cancel? Is there an emergency exit?
4Consistency and standardsAre the same actions/words used consistently? Does it follow platform conventions?
5Error preventionDoes the design prevent errors before they happen? (confirmations, constraints, defaults)
6Recognition rather than recallAre options visible? Can users recognize rather than remember?
7Flexibility and efficiency of useAre there shortcuts for experts? Can users customize frequent actions?
8Aesthetic and minimalist designIs every element necessary? Does extra information compete with relevant info?
9Help users recognize, diagnose, and recover from errorsAre error messages helpful? Do they explain what went wrong and how to fix it?
10Help and documentationIs help available? Is it searchable, task-oriented, and concise?

Evaluation Process

  1. Define scope: Which screens/flows to evaluate
  2. Walk through the interface 2-3 times with different user tasks
  3. Flag violations: Note each violation with heuristic #, location, description
  4. Rate severity: 0-4 scale for each violation
  5. Prioritize: Fix severity 4 and 3 first
  6. Report: Organize findings by severity, not by heuristic number

Output Format

markdown
# Heuristic Evaluation: {Product/Feature}

## Summary
- Total violations found: {N}
- Severity 4 (catastrophe): {N}
- Severity 3 (major): {N}
- Severity 2 (minor): {N}
- Severity 1 (cosmetic): {N}

## Critical Issues (Severity 3-4)
| # | Location | Heuristic | Issue | Severity | Recommendation |
|---|----------|-----------|-------|----------|---------------|
| 1 | {screen/element} | {#N: name} | {description} | 3/4 | {fix} |

## Other Issues (Severity 1-2)
| # | Location | Heuristic | Issue | Severity |
|---|----------|-----------|-------|----------|
| ... | ... | ... | ... | ... |

Examples

Correct Application

Scenario: Evaluating a food delivery app checkout flow
LocationHeuristicIssueSeverity
Cart page#1 VisibilityNo loading indicator when adding items — user taps multiple times3
Payment#5 Error preventionNo confirmation before placing order — accidental orders happen4
Error screen#9 Error recovery"Error 500" with no explanation or retry button4
Address form#6 RecognitionUser must type full address instead of selecting from saved addresses2
Priority: Fix #5 and #9 immediately (severity 4) ✓

Incorrect Application

  • "The app looks ugly" → Not a heuristic violation. "Aesthetic and minimalist design" (#8) is about information hierarchy, not visual attractiveness. A specific violation would be: "Product page shows 15 data fields simultaneously, burying the price and 'Add to Cart' button."

Gotchas

  • 3-5 evaluators find 75% of issues: One evaluator finds ~35%. Diminishing returns after 5. If possible, have multiple evaluators work independently then merge findings.
  • Heuristic evaluation finds problems, not solutions: It tells you what's wrong, not how to fix it. Solution design is a separate step.
  • Not a substitute for user testing: Experts predict user behavior imperfectly. Some "violations" that experts flag don't bother real users, and some real problems experts miss.
  • Mobile vs desktop: Apply heuristics separately for each platform. Touch targets, screen real estate, and interaction patterns differ significantly.
  • Accessibility is not a heuristic: Nielsen's 10 don't explicitly cover accessibility (color contrast, screen reader support, keyboard navigation). Add WCAG checks separately.

References

  • For WCAG accessibility checklist, see
    references/wcag-checklist.md