IBM: Judy, can you tell us the primary differences between WCAG 1.0 and WCAG 2.0?
JB: There are many improvements in WCAG 2.0, which W3C/WAI finalized in December 2008, as compared with the previous version.
- WCAG 2.0 can be applied to any technology used on the Web, so it is more flexible for developers. For instance, WCAG 2.0 allows the use of scripting. WCAG 2.0 therefore opens up all types of Web content to be more accessible for people with disabilities and older users.
- The provisions in WCAG 2.0 can be more precisely tested. This enables developers to know when they have met the requirements of the standard.
- WCAG 2.0 was tested successfully across a broad range of Web technologies, languages, and types of Web sites before it was finalized; so, developers can use it with confidence.
- WCAG 2.0 is accompanied by extensive technical materials that provide developers with proven design approaches, but which also allow developers to use their own innovations to meet the requirements of WCAG 2.0, and to share their innovations with other developers.
- WCAG 2.0 was developed with input and implementation experience from all over the world. It is expected to become the unifying standard for Web content accessibility.
IBM: What were some of the challenges your Working Group faced in developing the new standard?
JB: The WCAG Working Group wanted to ensure that WCAG 2.0 could be used flexibly for developers, yet be more precisely testable so that developers and those evaluating accessibility would know with certainty that their Web content conformed to WCAG 2.0.
The Working Group also wanted WCAG 2.0 to apply to today's Web technologies as well as to emerging technologies. I believe the group achieved this by using a multi-layered approach:
On one level, the group decided on four guiding principles that must be applied to each Web technology to determine if it is accessible:
- Is it perceivable?
- Is it operable?
- Is it understandable?
- Is it robust?
The group developed general guidelines as another level. This is where you would find the normative, testable success criteria.
The final level is a set of techniques for specific Web technologies such as HTML, XHTML, CSS, and SMIL that the Working Group produced.
This took a lot of hard work on the part of the WCAG Working Group, but the result is that WCAG 2.0 lets developers have their cake (flexible design across a variety of technologies) and eat it too (better testability).
One of the other challenges that the WCAG Working Group encountered was keeping up with the amount of public comment received. This was due in part to the already widespread use of WCAG 1.0 — many organizations around the world were already using WCAG 1.0, so there was a wealth of experience, and a great variety of perspectives on what types of changes would be best to move WCAG 2.0 forward.
The W3C/WAI process encourages this kind of public feedback; we find that it adds greatly to the quality and usefulness of the final standard. The WCAG Working Group did an impressive job of considering and incorporating extensive feedback, and also working with many different organizations on implementation trials prior to finalizing WCAG 2.0.
W3C/WAI is grateful to the many individuals and organizations who offered constructive comments during the development of WCAG 2.0.
