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Wendy Chisholm
Web Accessibility Initiative, World Wide Web Consortium
MIT/LCS Room NE43-354
200 Technology Square
Cambridge, MA 02139
+1 206 706 5263
Email: wendy@w3.org


An overview of WCAG 2.0 materials including: technology-specific documentation and examples, test suite and implementation tests, and WCAG 1.0 to WCAG 2.0 transition support.


The Web Content Accessibility Guidelines Working Group (WCAG WG) has published several public Working Drafts of WCAG 2.0 [WCAG20] and intends to publish WCAG 2.0 as a World Wide Web Consortium (W3C) Recommendation contingent on successful maturation through the W3C Recommendation Track [REC]. The questions asked most often about WCAG 2.0 Working Drafts are, "How will I transition my WCAG 1.0 conforming site to WCAG 2.0? What are the differences between WCAG 1.0 and WCAG 2.0? My country's legislative body adopted WCAG 1.0 because we worked hard to convince them they should; what happens when you release WCAG 2.0?" Additionally, since WCAG 1.0 [WCAG10] is the basis of WCAG 2.0; a common question about WCAG 1.0 is, "How do I know when my content conforms to WCAG 1.0?"

This presentation will provide an overview of the materials that the WCAG WG is developing to address these and other questions. Discussion will cover the testing materials constructed to help evaluators determine if content meets WCAG 2.0 and the techniques documents written to provide examples for authors who want to create content that conforms to WCAG 2.0.

Please note that the work described in this paper is representative of October 2003. As work in progress, it is subject to ongoing change and may be updated, replaced, or obsoleted by other documents at any time. This work is part of the Web Accessibility Initiative (WAI) Activity of the W3C.

Differences between WCAG 1.0 and WCAG 2.0

It is likely that WCAG 2.0 will have a different structure, a more flexible priority scheme, and fewer checkpoints than WCAG 1.0. What is not yet clear (as of October 2003) are the differences between specific WCAG 1.0 and WCAG 2.0 checkpoints. Many WCAG 1.0 checkpoints have been moved into HTML Techniques or broadened to apply to more technologies (e.g., "Use W3C technologies" from WCAG 1.0 will become something like, "Use technologies that have been reviewed for and support accessibility features" in WCAG 2.0).

Another difference is the breadth of supporting documentation. When WCAG 1.0 was published in May 1999, the supporting documents were an FAQ, a Checklist, HTML Techniques, CSS Techniques, and Core Techniques. After WCAG 1.0 was published as a W3C Recommendation, the Education and Outreach Working Group published a variety of resources [WAIRES] including a Curriculum, Evaluating Web Sites for Accessibility, How People with Disabilities Use the Web, and Quicktip cards [QT]. In addition to working with the EOWG to update their resources, the WCAG WG will publish more extensive techniques documents and a test suite.

Transitioning from WCAG 1.0 to 2.0

People who are not familiar with WCAG 2.0 Working Drafts often ask, "If my site conforms to WCAG 1.0, will I need to redesign my site to conform to WCAG 2.0?" WCAG 2.0 is based on the same concepts as WCAG 1.0 but expresses them in more abstract guidelines and checkpoints while providing more specificity at the technology-specific level. Some of the WCAG 1.0 checkpoints are only applicable to HTML or CSS; WCAG 2.0 checkpoints will apply to a range of technologies. Therefore, it is expected that only minor changes will be required to transition a site from WCAG 1.0 to 2.0. The WCAG WG and EOWG will work together to provide materials to help ease transition from WCAG 1.0 to 2.0.

Technology-specific Test Criteria

WCAG 1.0 Techniques documents are collections of best practices: code examples and documentation that illustrate how to satisfy a checkpoint for HTML and CSS. Since WCAG 1.0 Techniques do not provide detailed testing procedures and some elements receive more thorough treatment than others, the Evaluation and Repair Tools Working Group developed the Techniques for Accessibility Evaluation and Repair Tools [AERT]. AERT provides detailed tests and test criteria to determine conformance to WCAG 1.0. AERT also includes suggestions for authoring tool and evaluation tool interfaces.

The following HTML-specific example is based on Technique 1.1.1 from AERT and does not represent consensus of the WCAG WG. This example is included to demonstrate the level of specificity that could be included in WCAG 2.0 HTML-specific test criteria.

Example HTML test criterion: All img elements have a valid "alt" attribute

Valid "alt" attribute:

The WCAG WG is incorporating test criteria for each technique. Test criteria will be part of the technique description and also made available in technology-specific checklists. Currently (October 2003), primary focus is on techniques specific to HTML as well as techniques that are not specific to any technology. For example, writing appropriate text equivalents is not specific to any technology but associating a text equivalent with an image using the img element and alt attribute is specific to HTML. The WCAG WG will develop techniques for CSS, SVG, and SMIL and plans to cover other W3C technologies and ECMAScript. It is expected that Adobe and Macromedia will publish techniques for PDF and Flash (respectively).

Implementation Testing

The W3C Recommendation Track has several stages: Working Draft, Candidate Recommendation, Proposed Recommendation, and Recommendation [REC]. A Candidate Recommendation is a document that W3C believes has been widely reviewed and satisfies the Working Group's technical requirements. W3C publishes a Candidate Recommendation to gather implementation experience.

For WCAG 2.0, implementation experience will include two types of testing:

  1. Test the specification to determine that it is implementable, translatable, and testable.
  2. Provide a test suite used to test conformance of content (implementations) to WCAG 2.0.

The WCAG WG will solicit volunteers who are willing to apply WCAG 2.0 to their own Web site and provide feedback about the use of WCAG 2.0 materials. Of the volunteers, the WCAG WG will select a handful that represent different types of Web sites: different purposes (e.g., e-commerce, news, portal, education), different languages (e.g., Japanese, Hebrew, Finnish), and different technologies (e.g., videos, real-time content, documents). The WCAG WG will work more closely with the handful that is chosen, but appreciates feedback from anyone.

To support the volunteers, the WCAG WG will construct a test suite to be used by developers to determine if content satisfies WCAG 2.0. By employing the test suite on a site during implementation testing, developers can provide feedback about the understandability, applicability and usefulness of the test suite. Feedback will be incorporated and increase the likelihood that WCAG 2.0 will mature through the W3C Recommendation track. After WCAG 2.0 is published as a Recommendation, the test suite will be available for developers to use to determine conformance to WCAG 2.0.

Currently (October 2003), the WCAG WG is designing a test plan in coordination with other W3C groups including the Quality Assurance Working Group, the Authoring Tool Accessibility Guidelines Working Group, and the User Agent Accessibility Guidelines Working Group. This presentation will provide an update on the design and construction of the test suite.


The WCAG WG is developing Techniques documents to help authors interpret and apply WCAG 2.0 to a variety of technologies. A test suite will be constructed to test the implementability of WCAG 2.0 as well as to test content for conformance to WCAG 2.0. Working with the EOWG, the WCAG WG will provide materials to ease the transition to WCAG 2.0. Feedback and involvement in these activities is encouraged.


[WCAG20] http://www.w3.org/TR/WCAG20/

[REC] http://www.w3.org/2003/06/Process-20030618/tr.html#Reports

[WCAG10] http://www.w3.org/TR/WCAG10/

[WAIRES] http://www.w3.org/WAI/Resources/

[QT] http://www.w3.org/WAI/QuickTips/

[AERT] http://www.w3.org/TR/AERT

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