Chapter 9 Design Guidance and Design Rationale Kevin

Chapter 9: Design Guidance and Design Rationale Kevin Juang David Bate Will Rodes

Topics ¡ Sources of Design Guidance l l l ¡ Design Principles l l ¡ ¡ Standards Guidelines Style guides Simplicity Structure Consistency Tolerance Accessibility Design Rationale

Design Guidance ¡ User Interface Standard l l A set of internationally agreed design principles or approaches Most common is ISO 9241 ¡ l Ergonomic requirements for office work with visual display terminals (VDTs) Situations to use ¡ ¡ ¡ Detailed starting point for development Publicize its use Client requires it

Design Guidance ¡ Design Guideline l Suggestion that is in between design principle and design rule in terms of detail

Design Guidance ¡ Style Guides l l l Collection of design rules and guidelines Commercial or customized Situations to use ¡ ¡ ¡ Applied starting point for development Target users already familiar Associate with certain products

Design Principles ¡ Simplicity l l Keep the interface natural to the users Break down complex tasks into subtasks

Design Principles ¡ Structure l l Group related features Use metaphors

Design Principles ¡ Consistency l l Leverage user’s mental model to aid learning and satisfaction Can enforce using style guides or GUI code reuse

Design Principles ¡ Tolerance l l l Use constraints Provide helpful error messages Emphasize recoverability ¡ ¡ Forward error recovery Backward error recovery

Accessibility ¡ ¡ ¡ The Principles of Universal Design W 3 C Web Content Accessibility Guidelines Section 508

Design Rationale ¡ Record l l ¡ Format l l ¡ Design decisions Reasoning behind those decisions Table sorted by date Brief text with illustrations when appropriate Advantages l l l Record design thoughts for future reference Communicate design decisions to others Aids technical support and marketing

Questions?