1. usability
   1. useful
   2. usable
   3. reliability
   4. accessibility
      1. Allow for user customisation
      2. Provide equivalent visual and auditory content and interface elements
      3. Provide compatibility with assistive technologies
      4. Follow operating system conventions.
      5. Allow access to all functionality from the keyboard alone
      6. Support efficient navigation by providing context and orientation information
   5. Part 11 of ISO 9241, the international standard Ergonomic requirements for office work with visual display terminals
      1. Effectiveness
      2. Efficiency
      3. Satisfaction
      4. learnability
   6. universal usability
   7. assistive technology
2. separability
3. multitasking
4. interaction design
5. user-centred design (UCD)
   1. Interface design
      1. An early focus on users and their tasks
      2. Empirical measurement
      3. iterations of designing, building and evaluating a system
   2. Accessibility
6. Evaluating users
   1. User observation
      1. field study
      2. controlled study
   2. Interviews
   3. Questionnaires (Likert scales and quantitative data)
7. Design principles
   1. Affordance
   2. Visibility
   3. Feedback
   4. Tolerance
8. Human–computer interaction
   1. feedback loop
   2. graphical user interfaces (GUIs)
      1. direct manipulation
   3. command-line interface
   4. web user interfaces (WUIs)
   5. tangible interface