Accessibility Usability What is usability Usability is the

Accessibility & Usability

What is usability? �Usability is the ease with which users of a system can use the system to accomplish their goals �In general, usability is qualitative, not quantitative

Nielsen’s Framework � Learnability - how easy is it for users to accomplish basic tasks the first time? � Efficiency – once the design is learned, how quickly can users accomplish tasks? � Memorability – when they return to a design after not using it, how quickly do they re-establish mastery of the system � Errors – how many errors do the users make, how severe, and how easily can they recover? � Satisfaction – how pleasant to use is the design?

Usability Testing �Testing is the measurement of ease of use of a product �Contrast with usability engineering, which is the process that ensures a product with good usability �Preferred method is to use actual users acting on a working system

The process �Get some users �Ask the users to perform representative tasks �Observe what they do, where they have issues, and where they don’t

Testing… continued �It’s important to test users in a real-world scenario �If they’re going to use the system alone, test them alone �If they’re going to use the system in groups, test them in groups �The observer shouldn’t step in to redirect attention or help out, let the user solve the problem on their own

Testing… continued again �It’s better to run a bunch of small tests through the design process than one big test at the end �Usability testing can influence the direction of the functionality as well as the design �It’s much easier to rework things at an early stage than it is at the end when you’re a week away from shipping

Usability Testing and the Design Process � Before starting the new design, test the old one to see what should be fixed � Test competitiors � Conduct a field study � Make paper prototypes of your design ideas, test them with users � Refine the design ideas and re-test � Gradually move to higher and higher fidelity � Inspect the design against guidelines � Once the final design is implemented, test it again, problems crop up in implementation

So, what’s a paper prototype? �It’s a drawing of your interface, including all of the popup windows and other widgets available

Exercise �Create a paper prototype for an interface to compose an email, it should: • Allow the user to select a recipient from their address book or type one in • Write out a subject for the email • Write the body of the email, including spell check and basic text formatting (bold, italics) • Send the email �Create all the widgets you’ll need, we’re going to test these

What is accessibility? �Degree to which a product is accessible by as many people as possible �Often the focus is on people with disabilities �Accessibility is often about not throwing up barriers to alternative devices �Graceful degradation of the interface

Standards & Guidelines �Section 508 of the US Rehabilitation Act �Web Accessibility Initiative (WAI) �Web Content Accessibility Guidelines (WCAG)

Section 508 � Text equivalent for every non-text element (images, video, etc. ) � Documents must be readable without associated stylesheet � Redundant text links for server-side imagemaps � Row and column headers for tables � Plugins or applets must comply as well � Forms must be usable by people with assistive technology � High contrast version for vision impaired

Web Content Accessibility Guidelines � Provide alternatives to non-textual content � Don’t rely on color alone � Use markup and stylesheets properly � Clarify natural language usage � Use tables that transform gracefully (only for tabular data) � Ensure that pages using new technology degrade gracefully � Allow user control of time-sensitive functionality � Design for device independence

Why do we do this?

Why do we do this? �Because it’s the right thing to do �Because it’s illegal not to