Usability Concepts

Device Classes

• Abstract devices to reduce complexity for the programmer:
  • No need to “learn” mobile devices (special markup, navigation style…).
• Trie to handle the specific requirements of mobile devices & voice
  • Max. In/Output, Navigation style...
• Device classes are groups of devices that behave similar from a users / usability perspective.

Usability driven definition of device classes

Usability Metrics

• Usability models that programmers understand!