Introduction

Usability and Accessibility

The power of the Web is in its universality. Access by everyone regardless of disability is an essential aspect.
-- Tim Berners-Lee, W3C Director and inventor of the World Wide Web

What is Usability?

As defined by Jakob Nielsen, 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. Essentially, web usability reflects how effectively a site's intended audience will be able to find desired information.

He describes it as having five primary components: Learnability, Efficiency, Memorability, Errors, and Satisfaction

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?

What is Accessibility?

Accessibility, on the other hand, focuses on who can use a site. A web site is accessible if it can be used as effectively - or ineffectively - by people with disabilities as by those without.

Usability is not the same acessibility. In fact, some of the factors that enhance usability for one group may prevent access by another. Forexample, Navigation icons may improve usability for for visually-oriented users and increase accessibility for users with reading or language disabilities while hindering those with non-graphics browsers.

Accessibility is an especially important issue for the Web because so much information is available there, and increasinly, only there. The Introduction to Web Accessibility tutorial at WebAIM states: The Web Offers Unprecedented Opportunities. The Internet is one of the best things that ever happened to people with disabilities. You may not have thought about it that way, but all you have to do is think back to the days before the Internet was as ubiquitous as it is today to see why this is so..

The major categories of disabilities, visual, hearing, motor,and cognitive, require different types of adaptations in the design of Web content. At present, it is difficult to address all of them. However, strategies that improve accessibility can help improve for all.

In the draft version 2.0 of the Web Content Accessibility Guidelines (WCAG), the W3C defines guidelines for five primary areas of accessibility: Perceivable, Operable, Navigable, Understandable, and Robust.

Perceivable

Ensure that all intended function and information can be presented in form(s) that can be perceived by any user - except those aspects that cannot be expressed in words.

Operable

Ensure that the interface elements in the content are operable by any user.

Navigable

Facilitate content orientation and navigation.

Understandable

Make it as easy as possible to understand the content and controls.

Robust.

Use Web technologies that maximize the ability of the content to work with current and future accessibility technologies and user agents.

Standards

There are two sets of criteria defining accessibility standards.

One set is formulated by the Web Accessibility Initiative (WAI) of the W3C. The Web Content Accessibility Guidelines (WCAG) version 1.0 were formally recommended by the Consortium in May, 1999. They are intended for content developers (page authors and site designers) and for developers of authoring tools. The 2.0 version is currently under development.

The second set of standards is part of Section 508 of the Federal Rehabilitation Act of 1873 as amended in 1998. The section addresses a number of areas of electronic and information technology. The 16 specific rules that apply to web development are in §1194.22 Web-based intranet and internet information and applications., published onthe web at section508.gov. While the regulations of section 508 apply specifically to all Federal agencies when they develop, procure, maintain, or use electronic and information technology, they should be taken into account by all web developers.

The two sets of standards and rules are not identical, but they have many points in common. There is a Side-by-side WCAG vs. 508 comparison by Jim Thatcher at JimThatcher.com. Thatcher also has a tutorial on Web Accessibility for Section 508, originally written for the Information Technology Technical Assistance and Training Center.

There are no formal standards for usability, but there are a lot of informal guidelines. Many of the requirements for accessibility also help improve usability for everyone.

What we will do in this course

• Concepts - important factors affacting usability and accessibility
• Techniques - ways to make web sites usable and accessible
• Tools - some current software tools for developing web sites

Usable Web Site

• You can design websites that
• Are pleasant and convenient for your users
• Let them accomplish their goals
• The key: think about your users
• Learn about them
• Watch them work, in their workplace
• Interview them, also in their workplace

Benefits of Usable Web sites

• Gaining a competitive edge
• Conversion rate is the percentage of visitors who take an action you want them to take, such a making a purchase
• Increasing the conversion rate lowers the cost of individual sales
• Ease of use is the most important driver of high conversion rates
• And there is gold in improving the conversion rate, which was 3.2% in May, 2003
• Reducing development and maintenance costs
• Learn about users first, and you will avoid
• Implementing features users don?t want
• Creating features that are annoying or inefficient
• High cost of making changes late in the development cycle
• Improving productivity
• For e-commerce, productivity means that users find what they want?and succeed in buying it
• For a company intranet, productivity means employees become more efficient
• Lowering support costs
• Calls to customer support are very expensive for the vendor
• A website that reduces support calls can save major dollars

Usability is part of HCI

• Human Computer Interaction is a discipline concerned with the design, evaluation and implementation of interactive computing systems for human use and with the study of the major phenomena surrounding them.? -- As defined by the Special Interest Group on Human-Computer Interaction (SIGCHI) of the Association for Computing Machinery (ACM)
• Effective HCI is important
• 50 years ago the cost of a computer would pay the salaries of 200 programmers for a year
• People were expected to work hard to save computer time
• Today the salary of one programmer for a year will buy 200 computers?each vastly more powerful than the early machines
• Now the goal is to make computers easy to use, to save people time

Goals of usability - To develop or improve 

• Safety
• Of users
• Of Data
• Utility - The services a system provides, such as 
• Information
• Instruction
• Ability to make purchases
• Entertainment
• Effectiveness  -- user's ability to achieve goals
• Find desired information
• Provide necessary data
• Utility and effectiveness are distinct
• A web site might provide all necessary services, but if users can?t find the items they want to buy, the site lacks effectiveness
• Efficiency
• A measure of how quickly users can accomplish their goals or finish their work using the system
• Appeal - How well users like the system
• First impressions
• Long-term satisfaction

Homework

Note: Homework for each week will normally be due on the following Tuesday. Assignments may be issued on both Tuesday and Thursday.

1. CREATE a home page for this course. You do not need to remove your work from previous courses.
   • Make a subdirectory in your web space on wyrd.hood.edu
   • Put an index.html page in the directory. At this stage, it does not need to be elaborate, but it should be clear, crisp, and legible. (Do NOT rely on browser defaults for styling.) It should use an external CSS stylesheet for styling. It must validate as 1.0 strict.
   • The index page will serve as a table of contents for your homework. It should have a Table of Contents section with links to other assignments.
2. Be sure you have an index.html page in your public_html directory so no one can see your file listings.
3. WRITE a report about the class Scavenger Hunt exercise.
   • Use correct standard English in complete sentences and paragraphs.
   • Include the results from the notes you made.
   • Identify any problems of usability, accessibility, or both.
   • Discuss what you learned from it.
   • Publish the report on your web site.
   • Link to the report from your homework table of contents.
4. Submit your assignment - it is the HW1 assignment on Blackboard.