1.2.12 Define the term usability



Usability = Ergonomics + Accessibility

  • Usability:the ease of use and learnability of a hardware or software. The object of use can be a software application, website, machine, process, or anything a human interacts with.


  • Accessibility:  Refers to the design of products for people with disabilities or specific needs.



  • Ergonomics: The scientific discipline concerned with the understanding of interactions among humans and other elements of a system.


  • Learnability: How easy is it for users to accomplish basic tasks the first time they encounter the design?

  • Efficiency: Once users have learned the design, how quickly can they perform tasks?

  • Memorability: When users return to the design after a period of not using it, how easily can they reestablish proficiency?

  • Errors: How many errors do users make, how severe are these errors, and how easily can they recover from the errors?


  • Satisfaction: How pleasant is it to use the design?