Introduction to Usability

What is Usability?

ISO (the International Standards Organization) defines usability as the extent to which a product can be used by specified users to achieve specified goals with effectiveness, efficiency and satisfaction in a specified context of use.

"Usability really just means making sure that something works well: that a person of average (or even below average) ability and experience can use the thing - whether it's a web site, remote control, or revolving door - for its intended purpose without getting hopelessly frustrated." - Steve Krug

What Makes a Web Site Usable?

In simple terms, to be usable a web site or application must be considered by the target users to be:

• Useful
  The site provides the information and functionality that users want in a format they can use
• Self-evident
  All aspects of the site are obvious to users, all available options are clear at all times
• Able to prevent and recover from errors
  Mistakes are difficult to make and easy to correct
• Beautiful
  The interface is visually appealing (studies show that a poor quality design affects users' perceptions of the quality of the system)
• Learn-able
  The structure and functionality are easy for users to understand and remember
• Efficient
  Users can quickly and easily accomplish their goals without unnecessary effort

You Are Not Your User

Usability is in the eye of the user... and you are not your user.

You know how your site is structured, you understand the terminology, you know what your organization does and how you do it, you know how your site works. This makes it impossible for you to accurately assess your site's usability.

The final product must be tailor-made for the users because ultimately their opinions are the only ones that count.