Usability assesses how easy website user interfaces are to use. The word ‘usability’ also refers to methods for improving ease-of-use during the design process.

Usability is defined by five quality components:

• 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?