CHI 2007 Course Notes
Presented at CHI 2007, San Jose, CA
May 1, 2007
University of California
Berkeley, CA 94720
Copyright is held by the author/owner(s).
CHI 2007, April 28-May 3, 2007, San Jose, California, USA.
CHI 2007 Course Notes i Caroline Boyden and Lucia Greco
Table of Contents
Instructor biographies iv
Objectives of the course v
Course notes, part 1 1
Course notes, part 2 6
CHI 2007 Course Notes iii Caroline Boyden and Lucia Greco
Caroline Boyden and Lucia Greco are members of the WebAccess working
group at UC Berkeley. The group focuses on technology, education, advocacy,
and policy for website developers and users.
Caroline Boyden is a designer and developer on the College of Letters & Science
Computer Resources web team. She has ten years of experience in website and
web application design, with an emphasis on accessibility.
Lucia Greco is the Assistive Technology Specialist for the Disabled Students
Program. She has provided disability awareness and technology training to
individuals, and organizations such as the City of Oakland and the Bay Area
Rapid Transit District.
CHI 2007 Course Notes iv Caroline Boyden and Lucia Greco
1. Introduction and background.
2. Overview of legal and market conditions affecting web accessibility in the
3. Review of types of disabilities and their effects on web user experience.
Perceptual, mobility, cognitive, and other impairments.
4. Demonstration of assistive technologies for the web. Screenreaders;
literacy software; system settings; input devices.
5. Common ground between accessibility modifications and general usability
improvement. Benefits of accessibility for all users.
6. Questions and answers. Discussion.
1. The standards: Section 508 and WCAG 1.0 checklists. WCAG 2.0 and
2. Beyond the standards: Tips and guidelines for development. A collection
of cheat sheets and best practices.
3. Automated testing tools: from free and web-based to enterprise-level.
4. Developer tests and tools: browser extensions and plugins.
5. End-user testing.
6. Accessibility for Web 2.0. Live review of an Ajax-based web application.
7. Questions and answers. Discussion.
Objectives of the course
After completing the course, attendees will be able to:
• Understand the legal and market conditions that affect web accessibility;
• Understand the major effects of perceptual, mobility, and cognitive
disabilities on web user experience;
• Know the benefits and limitations of assistive technologies;
• Recognize the advantages of accessibility enhancements for all users;
• Determine the most efficient combination of evaluation methods for their
• Use automated, developer, and end-user testing tools and techniques; and
• Incorporate knowledge of accessibility issues into their projects from the
CHI 2007 Course Notes v Caroline Boyden and Lucia Greco
CHI 2007 Course Notes vi Caroline Boyden and Lucia Greco
Is your website accessible to users of assistive technology? How do you know?
This course will provide you with practical knowledge and techniques to
understand accessibility, evaluate your sites and applications, and improve user
Attendees will learn:
• How perceptual, mobility, and cognitive disabilities affect user experience
• What assistive technologies are available, and how they work
• Strengths and weaknesses of different accessibility testing methods
• Tools and techniques anyone can use to evaluate and improve their
Course Notes, Part 1
Legal and market conditions in the U.S.
• Legal landscape
o Section 508 of the Rehabilitation Act of 1973 (as amended
1998) guarantees access to electronic and information technology
procured by federal agencies. The standards are based WCAG 1.0.
o Section 504 of the Rehabilitation Act requires any organization
receiving U.S. federal government funding to ensure accessibility to
o ADA (Americans with Disabilities Act) of 1990 applies to “places
of public accommodation.” It was enacted before the internet boom,
and has not yet been interpreted to apply to websites.
o In response to a lawsuit, the U.S. District Court for South Florida
held that the ADA did not apply to Southwest.com because the
ADA only applies to physical places of public accommodation. An
appeals court declined to take the case.
o New York’s Attorney General argued that ADA does apply to
websites in a complaint against Ramada.com and Priceline.com.
The companies settled out of court in 2004, agreeing to comply with
WCAG accessibility standards.
CHI 2007 Course Notes 1 Caroline Boyden and Lucia Greco
o The NFB (and a Berkeley student) sued Target.com under Title III
of the ADA. The suit states that Target.com is a service of Target
stores, which are physical places of public accommodation. In
September 2006, the U.S. District Court for Northern California
ruled that the case could proceed under the ADA.
• Structured negotiations
o Rather than relying on the possibly shaky ground of the ADA for a
lawsuit, disability advocates have had success in direct
negotiations with major corporations to improve websites and
o In the financial services industry, major banks such as Bank of
America, BankOne (now Chase), and Washington Mutual have
signed legally binding agreements to comply with Priority 1 and 2
of the WCAG.
o Agreements also apply to talking ATMs, tactile point-of-sale
devices, and other technologies.
• Demographics and market conditions
o Census data: 50 million Americans live with disabilities.
Seventy-six million are baby boomers, now beginning to hit
o Microsoft commissioned “The Market for Accessible Technology,” a
survey of working-age adults (18 to 64) focused on computer use
by persons with disabilities. The survey included task-based
questions about specific difficulties, so it captured users who do
not self-identify as having a disability. The survey found:
Many trends are converging to increase the number of
people affected: the U.S. population is aging; impairments
increase in number and severity with age; the average
lifespan is increasing; people are delaying retirement;
generational waves of computer adoption mean the
percentage of population using computers will continue to
Forty percent of computer-using adults are likely to benefit
from assistive technology; 17% are very likely.
o Effects of technology on incidence of disabilities
Life-saving medical advances mean more people are living
longer with disabilities.
CHI 2007 Course Notes 2 Caroline Boyden and Lucia Greco
Increased computer use among all ages means more
potential for RSI.
• Lainey Feingold, “Web Accessibility and the Law: Recent Legal
Developments and Advocacy Strategies,” California State University-
Northridge, Technology And Persons With Disabilities Conference, 2005
• Section 508 of the 1998 amendments to the 1973 Rehabilitation Act, 29
• Americans with Disabilities Act
• Southwest Airlines lawsuit
• Priceline.com and Ramada.com settlement
• Target.com lawsuit
• “The Market for Accessible Technology—The Wide Range of Abilities and
Its Impact on Computer Use”
Types of disabilities and their effects on web user experience
• Hearing impairments
o Examples: deafness, age-related hearing loss
o The syntax of American Sign Language is not at all similar to
spoken and written English; users who learn ASL first effectively
speak English as a second language.
o Closed-captioning in web multimedia is accessible to deaf-blind
users with Braille displays.
• Mobility and physical impairments
o Examples: Repetitive stress injuries, cerebral palsy, quadriplegia.
CHI 2007 Course Notes 3 Caroline Boyden and Lucia Greco
o Users who cannot control a mouse can tab through web pages
element by element; if an element is not focusable by the keyboard,
it is inaccessible.
CHI 2007 Course Notes 4 Caroline Boyden and Lucia Greco
o Users with extremely limited movement may have a switch device
with a virtual keyboard; to type, the software cycles through every
key and the user activates the switch when the appropriate key is in
o Voice input software to control web browsers navigates one
element at a time, similar to keyboard-only navigation. Users
depend on consistent, concise labeling for efficient browsing.
Heavy use of voice input can cause damage to vocal cords.
• Cognitive impairments
o Examples: ADD, dyslexia, learning disabilities, Asperger syndrome.
o Nonverbal cues (color, typography) increase understanding when
o Literacy software assists users by highlighting and reading aloud at
the same time.
• Visual impairments
o Examples: Blindness, low vision (contrast or peripheral vision),
color deficiency, age-related vision changes
o Users may alter color combinations to increase contrast, reduce
glare, or reduce distraction. Individual color scheme preferences
vary widely depending on the nature and severity of the disability.
o Small print becomes increasingly difficult to read with age. Older
users and low-vision users will decrease screen resolution or
increase default text size.
o Magnification software can make elements up to 50 times larger.
Users lose the context of elements surrounding what they
o Screenreaders work by intercepting the information sent from the
application to the video driver. Output can be rendered as speech
or as Braille on a refreshable display.
o A screenreader requires that the user construct a mental model of a
screen by listening to its parts one at a time. Proficient users can
skip back and forth easily.
• Other impairments
o Chronic fatigue, seizure disorders
CHI 2007 Course Notes 5 Caroline Boyden and Lucia Greco
Assistive technologies demonstration and discussion
o JAWS for Windows:
o VoiceOver for Mac: http://www.apple.com/accessibility/voiceover/
• Literacy software
o WYNN for Windows:
• System settings
o Mac: http://www.apple.com/accessibility/
• Alternative input: Keyboard-only navigation
Common ground between accessibility and general usability; other
• Accessibility is a form of usability. Just as curb cuts improved life for
many in addition to wheelchair users, web accessibility modifications also
benefit non-disabled users.
• Google is blind. Since search engines have not (yet!) come up with
anything that can interpret images and media the way a sighted person
does, they rely on the text content of a site to index and link it correctly.
• Workplace and public-access computers are mute. Corporate
workstations and public-access computers often either have no capacity
for sound, or have the sound turned off. Computer users in shared offices
or public spaces may keep their sound low or off to avoid disturbing
others. Captions and transcripts make audio content available in these
• Preventing and accommodating RSI is a good thing. Keyboard navigation
increases efficiency and decreases unnecessary hand movements.
• Semantic markup requires up-front thinking about page. Good information
architecture leads to an accessible, usable site.
CHI 2007 Course Notes 6 Caroline Boyden and Lucia Greco
• Appropriate contrast increases readability for all, from the elderly to the
Course Notes, Part 2
• Section 508
o Standards: http://www.section508.gov/index.cfm?
o Commentary: http://webaim.org/standards/508/checklist.php
• WCAG 1.0
o Standards: http://www.w3.org/TR/WAI-WEBCONTENT/
o Techniques: http://www.w3.org/TR/WAI-WEBCONTENT-TECHS/
• WCAG 2.0
o Standards: http://www.w3.org/TR/WCAG20/complete.html
o Commentary: http://www.w3.org/TR/UNDERSTANDING-WCAG20/
o Techniques: http://www.w3.org/TR/WCAG20-TECHS/
o Controversy: http://alistapart.com/articles/tohellwithwcag2/
• If a site isn't compliant with one of these sets of standards, that
guarantees it's not accessible. If it is compliant, however, that doesn't
guarantee it is accessible.
Beyond the standards
Top ten tips and fixes, as hammered out over a year and a half of website
1. Skip navigation links. Particularly useful for screenreader and
keyboard-only users. Skip links should be visible. Expands on section
508 rule (o).
2. Heading elements, used correctly.
3. CSS for layout and typography. Flexible, semantic.
CHI 2007 Course Notes 7 Caroline Boyden and Lucia Greco
4. Images: Use sensible ALT text, left empty if the image is purely
decorative. Expands on Section 508 rule (a) / WCAG 1.0 checkpoint
5. Color: Use sufficient contrast, and do not rely on color alone to convey
meaning. Expands on Section 508 rule (c) / WCAG 1.0 checkpoint 2.1
6. Create unique names for links, with the most useful information at
the beginning of the link text.
7. Use “Go” buttons with drop-down lists used for navigation. Anything
that acts onChange will trap screenreader and keyboard-only users.
8. Label and order form fields. Unlabeled or mislabeled form fields are
a killer for screenreader users on any interactive site. Form instructions
should appear before the fields they apply to. Expands on Section 508
9. Manage tab order for efficient keyboarding.
10. No more text-only alternatives. Don't maintain a mirror (even an
automatically-generated one). Text-only sites do nothing for users with
mobility impairments, and are worse for users with learning disabilities
and other cognitive impairments. Makes moot Section 508 rule (k) /
WCAG 1.0 checkpoint 11.4.
More cheat sheets:
• Jakob Nielsen's report on accessibility:
• National Cancer Institute recommendations:
http://portal.acm.org/citation.cfm?doid=947226.947227; or with additional
• Dive Into Accessibility's tips by type of disability:
• The W3C's short list: http://www.w3.org/WAI/References/QuickTips/
Automated testing tools
• Validate first: pick a DOCTYPE and stick to it. Browser differences are bad
enough with clean, valid code. Anything worse, and the problems multiply.
• Free and web-based tools
CHI 2007 Course Notes 8 Caroline Boyden and Lucia Greco
o Cynthia Says. http://www.cynthiasays.com/ The Firefox Web
Developer Toolbar uses this site by default. It validates to either
Section 508 or WCAG, with options on level of warnings. Results
are in the form of a tabular report, with a pass/fail note at the top.
CHI 2007 Course Notes 9 Caroline Boyden and Lucia Greco
o WebXact. http://webxact.watchfire.com/ScanForm.aspx This
service is a descendant of Bobby, one of the first online
accessibility tools. It checks for compliance with WCAG by default;
the advanced options allow checking against Section 508. Results
are more detailed and warnings are easier to interpret.
o WAVE. http://www.wave.webaim.org/ The WAVE doesn't produce a
report or a pass/fail mark. It redisplays the page with icons inserted
whenever there's an error (red), a warning (yellow), or an
accessibility feature (green). It also inserts icons pointing out
structural markup features such as DIVs, lists, tables, etc. Good for
users of WYSIWYG tools such as Dreamweaver.
• Enterprise-level tools
o Jim Thatcher (http://www.jimthatcher.com/testing.htm) evaluated
six automated testing tools using 40 criteria. Two tools, Deque's
Ramp Ascend (http://www.deque.com/products/ramp/index.php)
and Parasoft's WebKing
were the tops in criteria passed, with 38 and 34 respectively.
o Ramp Ascend will spider an entire site and report violations of
Section 508, WCAG 1.0, or both at once. It can automatically repair
many common violations, and guides users through some
checkpoints that require judgment.
• Automated testing tools are good for speed, efficiency, and catching
oversights and stupid mistakes.
• W3C's HTML validator: http://validator.w3.org/
• W3C's CSS validator: http://jigsaw.w3.org/css-validator/
Developer testing tools
• Firefox Web Developer Toolbar: https://addons.mozilla.org/firefox/60/
• Firefox Web Accessibility Extension: https://addons.mozilla.org/firefox/
• IE Accessibility Toolbar: http://www.visionaustralia.org.au/info.aspx?
CHI 2007 Course Notes 10 Caroline Boyden and Lucia Greco
Developer tests, primary
1. Images off
2. Keyboard only, no mouse
3. Mouse only, no keyboard
4. Stylesheets off
6. Colorblind simulation – see Vischeck, http://www.vischeck.com/ and
Juicy Studio, http://juicystudio.com/services/colourcontrast.php
7. Extra-large text sizes
More developer tests
1. Text-only browser – see Lynx, http://lynx.browser.org/
important if you're doing Ajax or any heavy DOM scripting)
3. High-contrast settings
4. Grayscale monitor
5. Readability testing
• Multiple Firefox installations:
• Multiple IE installations: http://tredosoft.com/Multiple_IE
• Readability testing: http://juicystudio.com/services/readability.php
• In a paper presented at CHI 2005
(http://doi.acm.org/10.1145/1054972.1054979), Jennifer Mankoff, Holly
Fait, and Tu Tran reported on the relative effectiveness of different testing
methods for screenreader accessibility. Their results suggest that of the
more "discount" methods, testing by sighted developers using
screenreaders is the most effective.
CHI 2007 Course Notes 11 Caroline Boyden and Lucia Greco
• For a screenreader user: average training time to use the software is 40
hours. Approximately one-third of this is devoted to using the
screenreader with a browser.
• It can be hard to separate problems with the tool (e.g., a screenreader)
from problems with the task.
• Assistive technology users have vastly different levels of experience with
technology and disabilities of varying severity.
• Assistive technologies should be tested in the default configuration.
• The most commonly-used screenreader customizations are verbosity,
speed, spoken punctuation, and typing echo.
• Think-aloud, interactive testing with developers and assistive technology
users together captures the most useful information. Mankoff, Fait, and
Tran’s control group is the best way to test.
Accessibility for Web 2.0
• The fundamental things apply.
o Start from a foundation of accessible HTML; then consider your
• The two overwhelming issues for Ajax sites are:
o Informing users that page content has changed; and
o Providing access to the changed content.
• IBM, Mozilla, Freedom Scientific, and others are developing a new
accessibility API, IAccessible2, to extend MSAA.
• IAccessible2: http://www-03.ibm.com/press/us/en/pressrelease/20773.wss
• Joe Clark, “Build Half a Product,”
• James Edwards, “AJAX and Screenreaders: When Can it Work?”
• WebAIM, “Accessibility of AJAX Applications,”
CHI 2007 Course Notes 12 Caroline Boyden and Lucia Greco
“Access Now, Inc. v. Southwest, D. C. Docket No. 02-21734 CV-PAS”, Sept 24,
Al Saif, Y., “Install multiple versions of IE on your PC,” Tredosoft, July 11, 2006,
“Americans with Disabilities Act Home Page”, US Department of Justice, Decem-
ber 20, 2006, http://ada.gov/
Caldwell, B., Chisholm, W., Slatin, J., and Vanderheiden, G., Eds., “Techniques
for WCAG 2.0, W3C Working Draft 27 April 2006,” W3C World Wide Web Con-
sortium, April 27, 2006, http://www.w3.org/TR/WCAG20-TECHS/
Caldwell, B., Chisholm, W., Slatin, J., and Vanderheiden, G., Eds., “Understand-
ing WCAG 2.0 W3C, Working Draft 27 April 2006,” W3C World Wide Web Con-
sortium, April 27, 2006, http://www.w3.org/TR/UNDERSTANDING-WCAG20/
Caldwell, B., Chisholm, W., Slatin, J., and Vanderheiden, G., Eds., “Web Content
Accessibility Guidelines 2.0, W3C Working Draft 27 April 2006,” W3C World
Wide Web Consortium, April 27, 2006, http://www.w3.org/TR/WCAG20/com-
Chishom, W., Vanderheiden, G., and Jacobs, I., Eds., “Techniques for Web Con-
tent Accessibility Guidelines 1.0, W3C Note 6 November 2000,” W3C World
Wide Web Consortium, November 6, 2000, http://www.w3.org/TR/WAI-WEB-
Chishom, W., Vanderheiden, G., and Jacobs, I., Eds., “Web Content Accessibility
Guidelines 1.0, W3C Recommendation 5-May-1999,” W3C World Wide Web
Consortium, May 5, 1999, http://www.w3.org/TR/WAI-WEBCONTENT/
Clark, J., “Build Half a Product,” edited speaking notes from a presentation given
at Iceweb 2006, Reykjavík, April 28, 2006, posted May 4, 2006,
Clark, J., “To Hell with WCAG 2,” A List Apart, May 23, 2006, http://alistapart.-
Colville, S., “Run Firefox 2.0 and 1.5 side by side,” Muffin Research Labs, Octo-
ber 5, 2006, http://muffinresearch.co.uk/archives/2006/10/25/run-firefox-20-
CHI 2007 Course Notes 13 Caroline Boyden and Lucia Greco
Coyne, K. P. and Nielsen, J., “Beyond ALT Text: Making the web easy to use for
users with disabilities,” Nielsen, Norman Group, October, 2001, Available at:
Edwards, J., “AJAX and Screenreaders: When Can it Work?” May 5, 2006, http://
Feingold, L.,“Web Accessibility and the Law: Recent Legal Developments and
Advocacy Strategies,” California State University-Northridge, Technology And
Persons With Disabilities Conference, 2005, http://www.csun.edu/cod/conf/2005/
Fishkind, A., “IBM Helps Disabled Users Get More From Assistive Technology,
on More Computer Platforms,” IBM Media Relations, December 14, 2006, http://
Henry, S. L. and Popolizio, P., Eds, “Quick Tips to Make Accessible Web Sites”
W3C World Wide Web Consortium, January 2001, http://www.w3.org/WAI/Refer-
Lemon, G., “Readability Test,” Juicy Studio, United Kingdom, last update 2007,
Mankoff, J., Fait, H. and Tran, T., “Is your web page accessible?: a comparative
study of methods for assessing web page accessibility for the blind,” Conference
on Human Factors in Computing Systems, Proceedings of the SIGCHI confer-
ence on Human factors in computing systems, Portland, Oregon, 2005, pages:
41 – 50, ACM Press, New York, NY, 2005, Available at: http://portal.acm.org/cita-
“The Market for Accessible Technology—The Wide Range of Abilities and Its Im-
pact on Computer Use,” Forrester Research, Inc., Cambridge, MA, 2003,
“National Federation of the Blind v. Target,” Disability Rights Advocates, Berke-
ley, CA, September 7, 2006,
Pilgrim, M., “30 Days To A More Accessible Website,” Dive Into Accessibility,
January 2007, http://diveintoaccessibility.org/by_disability.html
“Section 508 of the 1998 amendments to the 1973 Rehabilitation Act 29 U.S.C.
CHI 2007 Course Notes 14 Caroline Boyden and Lucia Greco
“Spitzer Agreement to Make Web Sites Accessible to the Blind and Visually Im-
paired,” Office of the New York State Attorney General, August 19, 2004, http://
Thatcher, J.W., “Accessibility, Law and Target.com”, jimthatcher.com, Austin, TX,
Thatcher, J.W., “Web Accessibility Testing,” excerpt from Web Accessibility: Web
Standards and Regulatory Complaince, by Thatcher, J et al., Friends of Ed,
Berkeley, CA, July, 2006, reprinted by jimthatcher.com, Austin, TX, last update
August 2006, http://www.jimthatcher.com/testing.htm
Theofanos, M.F. and Reddish, J., “Bridging the Gap: Between Accessibility and
Usability,” Interactions, Vol. 10, Issue 6, p. 36-51, Nov-Dec 2003, ACM Press,
New York, NY, 2003, Available at: http://portal.acm.org/citation.cfm?
Theofanos, M.F. and Redish, J., “Bridging the Gap: Between Accessibility and
Usability,” Author’s version of Theofanos and Redish, reprinted and expanded
from Interactions, Vol. 10, Issue 6, p. 36-51, November-December 2003, ACM
Press, New York, NY, republished by Redish & Associates, last update 2007,
WebAIM, “WebAIM Section 508 Checklist,” last update 2007,
WebAIM, “Accessibility of AJAX Applications,” http://webaim.org/techniques/ajax/
All course materials and supplemental resources are available online at
CHI 2007 Course Notes 15 Caroline Boyden and Lucia Greco