Usability Created by Brett Oppegaard for Washington State University's DTC 375 class, spring 2009

What is usability? Web usability is the art and science of: • Knowing who is (or will be) using your site • Establishing goals for your site that serve those users • And making your site operate in a fashion that helps meet those goals Source: Web Usability for Dummies

How is usability measured? • Learnability – How easy is it for users to accomplish basic tasks the first time they encounter the design? When they arrive, how intuitively oriented are they? • Efficiency – Once users have encountered the design, how quickly can they perform tasks? Repeat visitors should be able to zip through the steps to do what they want. • Memorability – When users return to the site after a significant period away, how easily can they become proficient again? Source: Jakob Nielsen’s Alertbox

How is usability measured? • Errors – How many errors do users make? How severe are the errors? Where are they happening? And how easily can users recover after they have made such a mistake? • Satisfaction – How pleasant is it to use the design? How do you feel when navigating the site? Does it seem fun and engaging? • Utility – Utility is considered a separate quality attribute, but it is equally as important as usability. In short, does the site do what the user needs (or wants)? None of the difficult design work means anything to users if the users can only do things that they don’t want to do or the interface is too difficult to accomplish tasks that people come to the site to accomplish. Source: Jakob Nielsen’s Alertbox

Users leave! Never to return! What happens when? A Web site is difficult to use? A Web site doesn't clearly state what it does, what it offers,what its purpose is? Users get lost? Information is difficult to read? Key user questions aren't answered? Users cannot find what they want? Users leave! Never to return! Source: Jakob Nielsen’s Alertbox