CS 3724 Lecture Notes for Sep 13

I. Norman's design principles

Four principles of good design

• visible state and actions
• coherent and consistent conceptual model
• good mappings
• full and continuous feedback (vi vs emacs example)

Four points for failure

• users form inadequate goals
• system provides incomprehensible labels or icons
• unclear how to specify actions
• misleading feedback

II. Shneiderman's 8 Golden Rules

• Strive for consistency
• Enable frequent users to use shortcuts
• Offer informative feedback
• Design dialogs to yield closure
• Offer error prevention
• Permit easy reversal of actions
• Support internal locus of control
• Reduce short-term memory load

III. The Evolution of design

Design evolutionary, not revolutionary

Carroll and Rosson design characterization

• Design is a process, not a state
• Design process is nonhierarchical
• Design process is radically transformational
• Design involves discovery of new goals

Evolutionary design examples

• Telephone
• Typewriter
• PDA (why is Newton unsuccessful, Palm successful)