Web Content Accessibility Guidelines

The definitive guidelines for accessible web design are known as the Web Content Accessibility Guidelines or WCAG, for short. They are published by a group within the World Wide Web Consortium (W3C) called the Web Accessibility Initiative (WAI).

Like most guidelines, the WCAG are reviewed and updated at intervals. The full text of the current version, WCAG 1.0, is available at:

http://www.w3.org/TR/WAI-WEBCONTENT.

The next version, WCAG 2.0, is already being drafted and is available at:

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

The Guidelines

The WAI guidelines consist of 14 basic statements which can be used as general principles for accessible design. Each statment is broken down into one or more specific "checkpoints" which describe how to apply that guideline to particular features on web pages.

Each individual checkpoint is classed as Priority 1, 2 or 3.

Priority 1:
Web pages must comply otherwise some people will be unable to access information on a site.
Priority 2:
Web developers should try to incorporate these or else it will be very difficult to access information.
Priority 3:
Web devlopers may incorproate these otherwise some people will find it difficult to access information.

It therefore follows that any web page that does not comply with Priority 1 can be correctly labelled as "inaccessible".

In order to make things a bit clearer to web users, WAI has also defined three standards of accessibility known as "Conformance Levels":

Level 'A':
This is the most basic acccessibility standard. A site must comply with all of the Priority 1 checkpoints to achieve this standard.
Level 'AA':
A slightly higher standard. Sites must comply with all of the Priority 1 and 2 checkpoints to achieve this standard.
Level 'AAA':
Currently the highest standard of accessibility. Sites must comply with all Priority 1, 2 and 3 checkpoints to achieve this standard. The resulting site should be easy to use for all - regardless of what technology, specialist or otherwise, is being used to access it.

Which Conformance Level Should I Aim For?

The easy answer is "the highest level possible" but, generally speaking all web sites should achieve Level 'A'.

If you are re-developing a site or launching a new site, you should try to ensure that it achieves Level 'AA'.

True Level 'AAA' is extremely difficult to achieve in practice but compliance with the many of the Priority 3 checkpoints is possible and will greatly increase overall accessibility. Such sites are sometimes labelled as 'AA+'.