W3C/WAI WCAG 2.0 PAS Explanatory Report


Nearby: W3C PAS Submitter status, granted in October 2010. WS Package PAS

This report: http://www.w3.org/2011/pas/wcag2-er4

Table Of Content:

1. Introduction

This document presents the W3C/WAI Web Content Accessibility Guidelines (WCAG) 2.0 (editors Ben Caldwell, Michael Cooper, Gregg Vanderheiden, Loretta Guarino-Reid, W3C (MIT, ERCIM, Keio), 2008) being submitted by W3C for JTC 1 PAS transposition into an ISO/IEC International Standard.

This W3C Recommendation is within scope of the W3C PAS Submitter's original application and is part of the Core Web technology stack that W3C is continually maintaining and evolving. The conditions for the recognition of W3C as a PAS Submitter have not changed since approval of W3C as a PAS Submitter.

W3C believes that this submission is not appropriate for assignment to any existing JTC 1 subcommittee, as this submission does not fall within one unique JTC 1 structure, and therefore requests that the JTC 1 Secretariat perform the duties normally assigned to a subcommittee secretariat. W3C notes that the JTC 1 Secretariat might use the accessibility expertise available in SWG-Accessibility, SC 35, and SC 36.

The W3C/WAI WCAG 2.0 specification URL, and first publication date, along with the final International Standards ISO/IEC title and number we are requesting, is:

Number Title URL
40500 W3C WAI Web Content Accessibility Guidelines (WCAG) 2.0 http://www.w3.org/TR/2008/REC-WCAG20-20081211/

The remainder of this Introduction section addresses the strategic interests in Interoperability, and in Cultural and Linguistic Adaptability. Subsequent sections address the JTC 1 PAS criteria listed in the Document-Related Criteria (mapping to the section 7.4 in JTC 1 Standing Document on PAS).

1.1. Strategic values

Accessibility of the Web for people with disabilities is a fundamental aspect of a universal Web. The W3C/WAI Web Content Accessibility Guidelines (WCAG) 2.0 has gained international recognition by governments and organizations as the authoritative reference for accessible web content authoring. WCAG 2.0 defines the functional requirements for accessible web content, including websites and web applications; and it provides normative, testable criteria for meeting these requirements.

Web Content Accessibility Guidelines (WCAG) 2.0 explains how to make Web content more accessible to people with disabilities. Web "content" generally refers to the information in a Web page or Web application, including text, images, forms, sounds, and video. Following these guidelines makes content accessible to a wider range of people with disabilities, including blindness and low vision, deafness and hearing loss, learning disabilities, cognitive limitations, limited movement, speech disabilities, photosensitivity, and combinations of these. Following these guidelines also often makes Web content more usable to users in general. Four main principles are at the heart of WCAG 2.0: that web content should be perceivable, operable, understandable, and robust.

WCAG 2.0 is one of a set of three WAI guidelines that also include the Authoring Tool Accessibility Guidelines (ATAG), which address accessibility of applications used to create and produce web content, including HTML editors, content management systems (CMS), blogging and Wiki applications; and the User Agent Accessibility Guidelines (UAAG), which address accessibility of browsers and media players, and their interoperability with assistive technologies. These three essential components of web accessibility provide guidance applicable to all web technical specifications; including for instance W3C technologies such as HTML, XML, CSS, SVG, SMIL, as well as non-W3C technologies. They are complemented by Accessible Rich Internet Applications (WAI-ARIA) which supports WAI guidelines and provides functionality to support accessibility of dynamic, interactive web content. The following diagram illustrates the relationship between the three WAI guidelines.

illustration showing the guidelines for the different components, detailed description at http://www.w3.org/WAI/intro/components-desc.html#guide

Uniform adoption of WCAG 2.0 as the standard for accessible web content accelerates the development and implementation of browsers, media players, authoring tools, and assistive technologies that support a common set of accessibility features; it facilitates knowledge exchange and capacity building for web accessibility practitioners; and it supports cost-effective uptake of accessibility solutions by developers and other stakeholders. Interoperability between mainstream web technologies and assistive technologies such as screen readers, screen magnifiers, and speech recognition is made possible by adoption of a common reference standard for web content accessibility. By supporting development and advancement of a harmonized ecosystem for web accessibility, uniform adoption of WCAG 2.0 increases the level of web accessibility for people with disabilities.

The promotion of WCAG 2.0 to an ISO/IEC International Standard would contribute to its referenceability, promote more uniform adoption, and be expected to promote an even greater level of interoperability and international harmonization around a single set of technical requirements for web accessibility.

All W3C technologies are reviewed by the W3C Internationalization Activity during their development. The W3C standards development process is open to all participants, regardless of cultural or linguistic origins. During the development of WCAG 2.0, review was sought from people interested in web accessiblity from different stakeholder groups in many different countries. WCAG 2.0 was translated into some other languages during its development phase to facilitate those reviews, and changes recommended and made accordingly to promote linguistic adaptability of the completed standard. Additional translations have been made since it was completed.

WCAG 2.0 consequently supports accessibility of web content, running on a variety of platforms and frameworks, independently of cultural or linguistic parameters.

2. Document Related Criteria (7.4 in JTC 1 Standing Document on PAS)

The following sections use the numbering from section 7.4 of JTC 1 Standing Document 9 -- Guide to the Transposition of Publicly Available Specifications Into International Standards.

7.4.1 Quality

Within its scope the specification shall completely describe the functionality (in terms of interfaces, protocols, formats, etc) necessary for an implementation of the PAS. If it is based on a product, it shall include all the functionality necessary to achieve the stated level of compatibility or interoperability in a product independent manner. Completeness

  1. How well are all interfaces specified?
  2. How easily can implementation take place without need of additional descriptions?
  3. What proof exists for successful implementations (e.g. availability of test results for media standards)?

The W3C/WAI WCAG 2.0 specification being submitted followed the W3C standards development process. W3C standards are written in US English with semantics for terms imposed by various formal mechanisms. W3C provides authoring templates and tools, and employs vetted rules for the publication of documents to help Working Groups maintain consistent quality.

As a W3C Recommendation document, W3C/WAI WCAG 2.0 successfully passed the Candidate Recommendation stage of the W3C standards development process. In this development stage, independent implementations of the specifications are documented to demonstrate applicability and implementability of the standard in practice. The implementation testing process for WCAG 2.0 included testing multiple implementations of all normative features of WCAG 2.0 across different operating systems, browsers, assistive technologies; across a variety of types of content; and in diverse of languages and scripts. Documentation of successful implementations as of the end of the Candidate Recommendation period for WCAG 2.0 was presented in the WCAG 2.0 Implementation Report, which included detailed sub-reports.

W3C/WAI WCAG 2.0 is self-sufficient with regard to specification compliance; and, even though it does not mandate the scope of any particular implementation, it requires that no implementation violates any mandatory requirement listed in its Conformance section. Extensive supporting technical and educational resources are freely available on the W3C/WAI website, though these are not required for specification compliance.

The next sections provide detail on testing, conformance, implementation experience, and more. Clarity

  1. What means are used to provide definitive descriptions beyond straight text?
  2. What tables, figures, and reference materials are used to remove ambiguity?
  3. What contextual material is provided to educate the reader?

W3C/WAI WCAG 2.0 includes multiple layers of guidance. Technical requirements are specifically designed as testable statements, called "success criteria," that define unambiguous criteria for determining if functional accessibility requirements have been met with regard to web content, websites and web applications. These success criteria are organized under guidelines and principles to reinforce the context of the requirements and to provide greater clarity with regard to their intent. In order to meet the needs of different groups and different situations, three levels of conformance are defined for success criteria: A (lowest), AA, and AAA (highest). Additional information on WCAG levels can be found in Understanding Levels of Conformance.

Normative and non-normative sections of the specification are clearly highlighted, and a glossary is provided to define key terminology in the context of this particular specification. Extensive freely available supporting technical and educational material is provided and referenced from the respective sections of the specification. This includes background material to help developers better understand the intent and impact of the requirements, and techniques to help developers implement accessibility features according to the requirements.

The additional supporting materials are published separately from the stable W3C/WAI WCAG 2.0 specification so that they can be updated and expanded periodically to reflect current best practices. These materials include Understanding WCAG 2.0 and Techniques for WCAG 2.0. Testability

The extent, use and availability of conformance/interoperability tests or means of implementation verification (e.g. availability of reference material for magnetic media) shall be described, as well as the provisions the specification has for testability.

The specification shall have had sufficient review over an extended time period to characterise it as being stable.

W3C/WAI WCAG 2.0 includes an extensive Conformance section that normatively describes and enables conformance declarations across a broad variety of web technologies and environments. The conformance requirements align with the individual Success Criteria that are designed as testable statements and structured in a hierarchy of functional requirements. Tests, including common failures and sufficient techniques for every success criteria, are defined in Techniques for WCAG 2.0.

WCAG 2.0 received extensive review and refinement during its multi-year development, with participation and contributions from industry, disability and other user organizations, researchers, government representatives and other key stakeholders over the course of multiple review cycles. It has been considered stable since its publication in December 2008. Stability

  1. How long has the specification existed, unchanged, since some form of verification (e.g. prototype testing, paper analysis, full interoperability tests) has been achieved?
  2. To what extent and for how long have products been implemented using the specification?
  3. What mechanisms are in place to track versions, fixes, and addenda?

W3C/WAI WCAG 2.0 was published in December 2008 and has remained unchanged for the three years since. The implementation tests, which included interoperability tests with assistive technologies, described in discussion of the Candidate Recommendation stage above were completed in October 2008, prior to completion of the W3C standards development process in December of that year.

The specification has gained wide popularity among policy makers and end-users, and has become the web accessibility standard of choice among web developers worldwide. It has been translated into 18 languages to date, of which 8 translations have been promoted to Authorized W3C Translations after meeting requirements in the Policy for W3C authorized translations. Additional authorized translations are under development.

The specification has been adopted and implemented by many organizations around the world, and has proven to be a reliable and stable reference for web accessibility. The versioning of WCAG and the management of errors are in accordance with the W3C process. In particular, the respective W3C/WAI Working Group follows the Errata Management procedures in the W3C Process Document. To date, only a few editorial errors have been observed. Availability

  1. Where is the specification available (e.g. one source, multinational locations, what types of distributors)?
  2. How long has the specification been available?
  3. Has the distribution been widespread or restricted? (describe situation)
  4. What are the costs associated with specification availability?

All W3C specifications, including W3C Recommendation track documents (the highest level for a W3C standard) are available throughout their development for royalty-free download, without registration, through the W3C website, located at: http://www.w3.org/standards/.

W3C/WAI WCAG 2.0 has been available as a finalized W3C Recommendation under the same conditions since December 2008 at the URL http://www.w3.org/TR/2008/REC-WCAG20-20081211/.

W3C/WAI WCAG 2.0 and all its supporting technical and educational materials are distributed and promoted without fee or restriction internationally by W3C/WAI as well as by organizations and governments around the world.

7.4.2 Consensus

The accompanying report shall describe the extent of (inter)national consensus that the document has already achieved. Development Consensus

  1. Describe the process by which the specification was developed.
  2. Describe the process by which the specification was approved.
  3. What “levels” of approval have been obtained?

The W3C Process Document, already verified by JTC 1 for W3C's PAS submission process, governs the W3C standards development process. It promotes the goals of quality and fairness in technical decisions by encouraging consensus, requiring reviews both by W3C Member organizations and the public as part of the standard development process, and obliging the Working Group to respond to all comments.

In addition, as a specification developed within W3C/WAI, multi-stakeholder participation and review was actively sought out, including representation from industry, disability organizations, research, and government, to ensure that the consensus achieved represented the interests of different stakeholders of accessible web technologies.

As explained in this central W3C document, consensus is a core value of the W3C community. To promote it, the W3C process requires its Working Group Chairs and Staff Contacts to ensure that groups consider all legitimate views and objections, and endeavor to resolve them whether these views and objections are expressed by the active participants of the group or by others (e.g., another W3C group; a group in another organization; or the general public).

The W3C Process Document provides a definition for Consensus in the W3C context, describing the level of support for a decision reached among a set of eligible individuals:

The chain of steps leading from a Working Group draft to final W3C Recommendation status is followed by all W3C groups, including WCAG WG, and is described in the W3C PAS submitter status file.

The following image summarizes these document maturity levels:

W3C Process steps, starting at the bottom with Working Draft, then Last Call Working Draft, Candidate Recommendation, Proposed Recommendation, and Recommendation.

As with all W3C Recommendations, W3C/WAI WCAG 2.0 has a Status section describing its origin, the name of the W3C Working Group and Activity in charge of it at the time it was done, and more.

Under the W3C standards development process, when all issues raised during the various review steps have been resolved, this work has reached the highest level in the W3C process and becomes a W3C Recommendation. Response to User Requirements

  1. How and when were user requirements considered and utilised?
  2. To what extent have users demonstrated satisfaction?

W3C/WAI WCAG 2.0 is the result of extensive consideration and utilization of user requirements. During the development of WCAG 2.0, the specification benefitted from direct involvement of, coordination with and review by user organizations, including individuals with disabilities and representatives of people with disabilities, older people, and consumers in general. Several mechanisms supported by the W3C process were used, ranging from active participation of W3C Member organizations and Invited Experts, to broad public calls for review and to calls to invited contacts with specific stakeholder expertise, to ensure representation of all stakeholders including those end-users.

The W3C standards development process requires Working Groups to respond to all comments from W3C Member organizations as well as from the public, regardless of their direct or indirect involvement with the Working Group. Working Groups are further required to document comments and to credibly demonstrate their satisfactory resolution in a transparent way. W3C/WAI WCAG 2.0 has followed these procedures just as with other W3C standards during its development process. Market Acceptance

  1. How widespread is the market acceptance today? Anticipated?
  2. What evidence is there of market acceptance in the literature?

W3C/WAI WCAG 2.0 is internationally recognized by organizations and governments as the authoritative reference for web accessibility. Supporting testimonials at the time of WCAG 2.0's publication as a W3C Recommendation included UNESCO, ISOC, two European Commissioners, the US Access Board, G3ict, Adobe, HP, IBM, Microsoft, and a number of user and research organizations.

WCAG 2.0 succeeds Web Content Accessibility Guidelines 1.0 (WCAG 1.0), which was published as a W3C Recommendation in May 1999. Although it is possible to conform either to WCAG 1.0 or to WCAG 2.0, or to both, W3C recommends using WCAG 2.0 for its many advantages for developers as well as for people with disabilities.

Many governments that had previously adopted WCAG 1.0, or that had developed their own web accessibility standards, have already or are currently holding proceedings to update their policies to reference WCAG 2.0. For example, both the United States and the European Commission are updating policies regarding procurement of government ICT to align with WCAG 2.0 for their requirements that relate to web content, while Australia and New Zealand have already done so, and Japan has updated its JIS standard for accessible web content to align with WCAG 2.0. This move is frequently supported by industry, for whom WCAG 2.0 provides an implementation advantage by virtue of its improved testability and greater flexibility across different Web technologies; by end-users, who prefer the enhanced accessibility for advanced web applications including dynamic and interactive web content afforded by WCAG 2.0; and likewise by governments interested in WCAG 2.0's applicability to accessibility of social media and other technologies supporting citizen participation. WCAG 2.0 has already found widespread implementation on different types of websites and applications from a variety of domains. Credibility

  1. What is the extent and use of conformance tests or means of implementation verification?
  2. What provisions does the specification have for testability?

Requirements in W3C/WAI WCAG 2.0 are specifically designed to be testable statements in order to support the assessment of websites and web applications. The specification also provides a clear Conformance section that defines the conditions for meeting these requirements.

Links from within W3C/WAI WCAG 2.0 lead to a customizable Quick Reference interface that links to an extensive collection of current WCAG 2.0 Techniques. These techniques are periodically updated to reflect the latest best practices and state-of-the-art in implementation. This reference, How to Meet WCAG 2.0: A customizable quick reference to Web Content Accessibility Guidelines 2.0 requirements (success criteria) and techniques, links to hundreds of state-of-the-art techniques and associated test statements. Expanded testing materials and a more detailed evaluation methodology are under development by a broad and collaborative community of WCAG 2.0 implementers.

7.4.3 Alignment

The specification should be aligned with existing JTC 1 standards or ongoing work and thus complement existing standards, architectures and style guides. Any conflicts with existing standards, architectures and style guides should be made clear and justified. Relationship to Existing Standards

  1. What international standards are closely related to the specification and how?
  2. To what international standards is the proposed specification a natural extension?
  3. How is the specification related to emerging and ongoing JTC 1 projects?

W3C/WAI WCAG 2.0 relates but does not overlap or conflict with international standards on accessibility in software and ICT. In particular, it has been drawn upon for extensive input into the user needs listed in ISO/IEC TR 29138-1:2009, Information technology -- Accessibility considerations for people with disabilities -- Part 1: User needs summary and cross-referenced with accessibility standards listed in ISO/IEC TR 29138-2:2009, Information technology -- Accessibility considerations for people with disabilities -- Part 2: Standards inventory.

W3C/WAI WCAG 2.0 is consistent with ISO/IEC Guide 71, which provides guidance to standards developers in addressing the needs of older persons and persons with disabilities; and complements existing standards and work within JTC 1 regarding accessibility of ICT, in particular the work of JTC 1 Special Working Group on Accessibility (SWG-A) and other subcommittees such as SC35 and SC36. Adaptability and Migration

  1. What adaptations (migrations) of either the specification or international standards would improve the relationship between the specification and international standards?
  2. How much flexibility does the PAS submitter have ?
  3. What are the longer-range plans for new/evolving specifications?

W3C Recommendations are developed through a rigorous, iterative process and are the result of many comments from different stakeholders throughout the different development stages. In particular W3C/WAI WCAG 2.0 has undergone a long and extensive development process and is the result of carefully aligned requirements and consensus-based resolutions.

W3C intends to provide maintenance as needed for this submission by providing complete replacement documents for subsequent PAS Transposition ballot approval. Given the stability, market acceptance, and unique nature of W3C/WAI WCAG 2.0, there is no identified need for adaptations at this time. Future updates, revisions, or development of the specification should continue through the respective W3C/WAI Working Group with the necessary expertise and experience for leading work in this particular domain, in parallel with the complementary authoring tool and user agent guidelines work. Likewise, translations, errata management, and other maintenance and support efforts should continue through the corresponding proven W3C processes.

The possibility of longer-range work on this standard has been considered by W3C/WAI, which is committed to pursue such work as needed with full attention to harmonization and forwards/backwards compatibility, drawing on the expanded community of users and implementors that has arisen around the development of WCAG 2.0. While WCAG 2.0 is considered a stable specification into the foreseeable future, W3C welcomes participation and input from JTC 1 country delegations into potential future work that may be needed. Substitution and Replacement

  1. What needs exist, if any, to replace an existing international standard? Rationale?
  2. What is the need and feasibility of using only a portion of the specification as an international standard?
  3. What portions, if any, of the specification do not belong in an international standard (e.g. too implementation specific)?

W3C/WAI WCAG 2.0 is unique and ground-breaking work. It does not replace or conflict with existing international standards but complements them in the domain of web accessibility.

W3C licensing and intellectual property rights do not permit the extraction of portions of W3C specifications, as this would likely change their meaning or otherwise threaten interoperability. This is particularly relevant for W3C/WAI WCAG 2.0, as each requirement has been carefully stated and aligned with other requirements to provide a single, interoperable set of requirements.

Additionally, the design of WCAG 2.0 is around a core normative set of provisions (success criteria), and all additional normative and non-normative portions of the document are carefully chosen to provide essential context for these normative provisions. All other layers of supporting materials, including detailed reference material on interpretation, and technical material supporting implementation of WCAG 2.0, were published in supporting documents (primarily Techniques for WCAG 2.0 and Understanding WCAG 2.0) to keep the specification itself limited to the stable functional requirements. The supporting documents have already been updated and expanded several times, as intended, to remain current with the latest technologies. WCAG 2.0 itself is technology-neutral (in that it defines accessibility of web content across any kind of web technology, for instance, HTML, XHTML, CSS, scripting, SMIL, text, ARIA, Flash, PDF, Silverlight, and more), and is expected to remain stable into the foreseeable future. Document Format and Style

  1. What plans, if any, exist to conform to JTC 1 document styles?

The production of all W3C specifications is driven by a set of W3C publication tools, templates, and rules that support accessibility and broad usability across different environments. W3C is capable of generating multiple output formats using our specification sources (e.g. HTML, PDF, plain text.) The intended publication mode for this submission would be to retain the essential aspects of the W3C publication. Should any updating of the publication require transposition to JTC 1 document styles, a primary consideration would be full accessibility support as defined by this specification, and full retention of linguistic and hyperlinking expected by one of the primary audiences for WCAG 2, the community of web developers.

Regarding final names and numbers in the ISO/IEC style, the table in the introduction section above provides the requested title and number (40500) for W3C/WAI WCAG 2.0 (using the assigned 40xxx numbering base allocated to W3C).

Editors Daniel Dardailler, Judy Brewer, Shadi Abou-Zahra
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