User Interface Design Principles – Exam Review
Remember: These principles are relatively time-invariant and guide better UI design across contexts.
1. Principle of User Profiling – "Know Who Your User Is"
- Identify users by role, not title.
- Users are diverse in background, skills, goals, and preferences.
- Mismatch between engineers/designers and users can cause poor design decisions.
Examples:
- UI for a programmer ≠ UI for a senior citizen.
- Expectations change over time as users gain experience.
- Use personas & empathy mapping to understand users.
2. Principle of Humility – "Listen to What Ordinary People Have to Say"
- Don’t assume you know best—users offer valuable insights.
- Feedback is important, but balance it with technical constraints.
- Lack of computer literacy ≠ lack of intelligence.
Examples:
- Use interviews & observations to gather insights.
- Don’t build solely based on user demands—consider feasibility.
3. Principle of Metaphor – "Borrow Behaviors from Familiar Systems"
- Familiarity aids learnability and usability.
- Icons, skeuomorphism, and anthropomorphism make systems intuitive.
- Be careful with over-reliance on color for meaning.
Examples:
- Trash bin icon for delete.
- Digital calculator mimicking physical layout.
4. Principle of Feature Exposure – "Let Users See Available Functions"
- UI should help, not hinder, task completion.
- Expose only necessary features—avoid clutter.
- Use progressive disclosure to reveal complexity gradually.
Examples:
- Microsoft Office toolbar shows most-used functions; users can customize.
- Firefox hides download icon until needed.
5. Principle of State Visualization – "Changes in Behavior Should Be Visible"
- Changes in state should reflect in UI appearance.
- Helps users know the system received their input.
- States can be indicated by text, icons, colors, or animations.
Examples:
- Visited vs unvisited hyperlink colors.
- Progress bars during downloads.
- Email unread messages in bold.
6. Principle of Coherence – "Be Internally & Externally Consistent"
- Internal consistency: same behavior/format across one system.
- External consistency: aligns with conventions in other systems.
- Consistency improves learnability and reduces errors.
Examples:
- CTRL+S saves in most software (external).
- All temperature units in the app use Celsius (internal).
7. Principle of ‘Safety’ – "Provide a Safety Net"
- Design for error tolerance and recovery.
- Anticipate mistakes—make them easy to prevent, detect, and correct.
- Error messages should be clear, helpful, and respectful.
Examples:
- Undo/redo in Word or Photoshop.
- Confirmation dialogs for irreversible actions.
- Spellcheck and grammar suggestions.
Key Takeaways for Exam:
- Be able to define each principle and explain its importance.
- Give real-world examples for each principle.
- Understand the relationship between principles (e.g., consistency aids learnability).
- Recognize good vs bad UI designs based on these principles.