Introduction to Web Design & Usability

Introduction to Usability

In the introductory discussion I asked you what Web design meant and who the stakeholders are for a Web site. Hopefully among the stakeholders that you identified you included the end-user or simply the user, who is, in many cases, also known as the customer or consumer.

Why do users come to a Web site? Why do any of us do anything? We have a need for something. Users go to a Web site to acquire something, for example, information or a product. In other words they need to accomplish a task. This is quintessentially the end-user's goal, and usability expert Jared Spool describes the behavior of a web site user as a hunter seeking it's prey in often unfamiliar or difficult terrain. So in order to satisfy the user as a stakeholder, first and foremost a Web site must provide the customer with what she wants, and as quickly and as easily as possible.

Usability denotes the ease with which end-users can employ a particular tool or other object in order to achieve a particular goal. Usability can also refer to the methods of measuring usability and the study of the principles behind an object's perceived efficiency or elegance. Jakob Nielsen, a sometimes contraversial usability guru, writes in Usability 101:

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?

from Jakob Nielsen's Alertbox - Usability 101

Usability should not be confused with capability. Usability is concerned with how the user interacts with the available technology, not what plug-ins and browser and operating system they have (though such accessibility issues are important).

For our concerns, when we talk about usability we're essentially asking about the site's utility, that is, how easy is it for a user to achieve their goal by using a given Web site? Does the Web site do what users need it to do? This question confronts the design and functionality of that Web site, and requires us to consider the user experience. It's not a question that's easy to answer; just ask Steve Krug. He wrote an entire book (Don't Make Me Think!) on uncovering what really goes on in a user's mind as s/he interacts with a Web site.