Usability Testing Patterns

Test Planning

Sample Size

• 5 users find ~85% of usability issues.
• 8-12 for quantitative confidence.
• Test with your target audience, not colleagues.

Task Design

• Scenario-based: "You want to send money to a friend who just bought you lunch."
• Not instruction-based: "Click the Send Money button in the top right."
• 5-7 tasks per session (30-45 minute sessions).
• Order from simple to complex.

Moderation

Questions to Ask

• "What are you thinking right now?"
• "What do you expect to happen?"
• "Is this what you expected?"
• "On a scale of 1-5, how easy was that?"

Questions to Avoid

• "Did you find that easy?" (leading)
• "Would you use this feature?" (hypothetical, unreliable)
• "Do you like the design?" (preference, not usability)

Rules

1. Don't help. Let users struggle (that's data).
2. Don't explain the design. If it needs explanation, it needs redesign.
3. Follow up with "why" after observing behavior.
4. Record sessions (with consent).

Analysis

• List all issues observed.
• Rate severity: critical (blocks task), major (causes confusion), minor (causes slight delay).
• Group by theme.
• Prioritize fixes by severity × frequency.