Dey Alexander: The five Es of usability

  • Effective
    • Completeness – was the task fully completed? Were the user’s goals met?
    • Accuracy – was the task completed successfully? Did the user get the right or correct result? How well was the work done?
  • Efficient
    • Speed – was the user able to complete the task quickly?
    • Effort – was the user able to complete the task without undue cognitive effort?
  • Engaging
    • Pleasant – did the user have a pleasant experience when working on the task?
    • Satisfying – was the user satisfied by the way in which the application supported her work?
  • Error tolerant
    • Error prevention – did the user interface help users avoid making errors? Were errors minor rather than major?
    • Error recovery – if the user made an error, did the interface assist them in making a successful recovery?
  • Easy to learn
    • Predictability – was the user able to work with some certainty because the user interface built on her previous knowledge?
    • Consistency – was the interface consistent, so that once a user learnt how to use part of the application, they were able to easily learn how to use another part?