Rantmedia. Web Design & Development

What is Usability?

Usability is a quality attribute that assesses how easy 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?

"On the Web, usability is a necessary condition for survival. If a website is difficult to use, people leave. If the homepage fails to clearly state what a company offers or what users can do on the site, people leave. If users get lost on a website, they leave. If a website's information is hard to read or doesn't answer users' key questions, they leave."

Jakob Nielsen - Usability Expert