The importance of Design

Instructions on door: “Press handle down and push.”

If you design something that is difficult or confusing to use, user’s won’t use it.

Bad design can be security or safety issue.

Passwords. Hard to use, badly designed, people work around it.

Three mile island.

• Visibility.
• Feedback. Give feedback that user’s action has had an affect on the system.

• Error messages.

  • What happened. What it wrong. Include name of application.
  • Why it happened? What went wrong? What was the impact? Avoid blame.
  • How do you fix it? Avoid “see administrator”.
  • Avoid colour coding as sole indicator.
• Constraints. User’s should be able to work out what operations are not available.
• Mapping. The relationship between the control and what it does.
• Consistency.
• Affordance.