Usability and User-Centered Design

Portfolio for Jonathan Reid

 

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?

--Jakob Nielsen, "Usability 101"

"Usability" is the ease of which a particular web site or application can be used. Usability is often conflated with functionality, because the two are closely intertwined, but the two are quite different. The world is full of software and web pages that are full of functionality but are lacking in usability. Everyone wants usable applications, but we have yet to stumble on the "magic bullet" that applies to all situations. This is because the audience varies, and these variations have to be taken into account when creating applications.

This is why user-centered design techniques are part of my core philosophy. I firmly believe that it is necessary to involve the user in the product creation process, though the degree and type of involvement depends on the project in question. For most projects, the users should be involved not only in the design but also the testing of the product.

Link: An essay on Goal Oriented Design from my blog.