[ROUGH CONCEPT DRAFT] Transitioning Web Sites from WCAG 1.0 to WCAG 2.0
Note: This document is a rough draft in
development, and should not be referenced or quoted under any circumstances.
$Date: Wednesday 17 January 2007 - 20:18:30changelog]
This guide highlights key steps for designers, developers, and project managers when transitioning a site from Web Content Accessibility Guidelines 1.0 (WCAG 1.0) to Web Content Accessibility Guidelines 2.0 (WCAG 2.0). Each step is introduced with a supporting resource document.
WCAG 2.0 builds on WCAG 1.0 and is designed to apply to more advanced Web technologies, be easier to use and understand, and be more precisely testable. Sites built to WCAG 1.0 will already be a long way to fulfilling WCAG 2.0 as it is backwards compatible with WCAG 1.0. As such, existing accessibility work is still valid and in many cases work needed to transition to WCAG 2.0 may be minimal.
For more information on the benefits of WCAG 2.0 please refer to "The benefits of transitioning to WCAG 2.0" (future link).
Having read the Overview the key differences you need to know are differences in approach and terminology (such as checkpoints changing to Success Criteria) , and how the new concept of Baseline underpins your Conformance claim.
Note: What we refer to as requirements in this page are the WCAG 1.0 Checkpoints and is the WCAG 2.0 Success Criteria.
To establish what requirements you will need to meet under WCAG 2.0 first decide your Baseline and Conformance levels. If your organisation already has an Accessibility Policy that is updated to WCAG 2.0, Baseline and Conformance should be outlined here.
If you want information to help you develop an Accessibility Policy the document Developing Organizational Policies on Web Accessibility outlines key considerations. "Transitioning Web Accessibility Policies from WCAG 1.0 to WCAG 2.0" is a future document which will provide guidance on transitioning Accessibility Policies.
Resource: About Baseline in WCAG 2.0 provides information about what the baseline concept is, key considerations when deciding a baseline and example baselines.
Once the Baseline is established there are a number of key things to understand
- What technologies are relied upon and not relied upon within your site.
- How Baseline impacts your Conformance claim.
- Dependant on Baseline and Conformance, what techniques will need to be implemented.
Note this will be revised after About Baselines in WCAG 2.0 is updated.
Resource: Conformance WCAG 2.0 provides information about levels of conformance, how to scope a site and how to write a conformance claim.
You will need to understand:
- How the WCAG 2.0 Conformance scheme works and differs from WCAG 1.0.
- How to scope a Web site using the WCAG 2.0 Conformance scheme.
- What things might impact what you choose for conformance such as internal policies and legal policies that exist for your country, region or organisation type.
Note that you might refine your conformance goals after you have completed a more in-depth analysis of the technical differences, as described below in section 3.
- Comparison of WCAG 1.0 Checkpoints to WCAG 2.0 maps those WCAG 1.0 Checkpoints that can be to WCAG 2.0 Success Criteria. Note that there is not a direct one to one mapping between WCAG 1.0 and WCAG 2.0.
- WCAG 2.0 Quick reference will help you determine what Success Criteria you will need to meet based on your Baseline and Conformance level.
Two key areas to review are:
3.1. Check what WCAG 1.0 Checkpoints map to WCAG 2.0 Success Criteria
Key questions to ask your self are:
- Have the WCAG 1.0 requirements that map to WCAG 2.0 already
been implemented in your site?
Review what techniques have you already met in WCAG 2.0 simply by following WCAG 1.0. For example if you have met checkpoint 1.1 "Provide a text equivalent for every non-text element" under WCAG 1.0 you will have met the Success Criteria for Guideline 1.1" Guideline 1.1 Provide text alternatives for all non-text content" under WCAG 2.0.
- Do WCAG 1.0 requirements that map to WCAG 2.0 have more refined
Success Criteria that you need to address?
Review if there is additional techniques added in WCAG 2.0. For example under WCAG 1.0 the checkpoint 2.2 "Ensure that foreground and background color combinations provide sufficient contrast" has a more clearly defined Success Criteria under WCAG 2.0: 1.4.1 "Text or diagrams, and their background, have a luminosity contrast ratio of at least 5:1".
- Are there requirements in WCAG 1.0 that your site didn't meet
that now meet WCAG 2.0?
There may be requirements that failed WCAG 1.0 but are a pass under WCAG 2.0 due to there being a clearer test criteria. For example under WCAG 1.0 checkpoint 7.1 "Until user agents allow users to control flickering, avoid causing the screen to flicker" it is recommended to avoid flickering content. Under WCAG 2.0 the Success criterion are more clearly defined by 2.3.1 "Content does not violate the general flash threshold or the red flash threshold" and 2.3.2 "Web units do not contain any components that flash more than three times in any 1-second period".
- Are there requirements in WCAG 1.0 that your site no longer
needs to meet in WCAG 2.0?
Some requirements from WCAG 1.0 are now no longer required in WCAG 2.0. For example Checkpoint 10.3 "Until user agents handle empty controls correctly, include default, place-holding characters in edit boxes and text areas". This does not mean however that you need to remove these as these checkpoints are still beneficial, having them will not mean your site fails WCAG 2.0.
3.2. Check new WCAG 2.0 Success Criteria
Review the quick reference document, Comparison of WCAG 1.0 checkpoints to WCAG 2.0 "New ones", for a list of new Success Criteria. Key questions to ask are:
- Which new WCAG 2.0 Success Criteria are already implemented in
your existing site?
You may find that new Success Criteria in WCAG 2.0 have already been met in your site. For example Success Criteria 1.3.5, "Information required to understand and operate content does not rely on shape, size, visual location, or orientation of components" may already have been met under under WCAG 1.0, checkpoint 2.1 "Ensure that all information conveyed with color is also available without color, for example from context or markup". This requirement is implied in WCAG 1.0 but is now explicit in WCAG 2.0.
- Which new WCAG 2.0 Success Criteria are not implemented in your
List new Success Criteria which may not already be implemented in your site. For example you may have error pages that do not clearly state to the user there is an error: 2.5.1 "If an input error is detected, the error is identified and described to the user in text".
- WCAG 2.0 Quick reference document allows you to list WCAG 2.0 Success Criteria and techniques for technologies in your Baseline.
- Implementation plan for accessibility provides an outline of how to plan and implement accessibility changes in your Web site(s)
Once you have reviewed the differences between WCAG 1.0 and 2.0, you can then plan changes to your site(s). To do this:
- Evaluate how your current site meets WCAG 2.0
Test the site against WCAG 2.0 according to the Level Success criterion set in your Conformance claim. The Evaluation section of "Improving the accessibility of your site provides further guidance on this.
- Prioritise changes necessary to meet WCAG
It is important to map out what work needs to be done and prioritize it. Work may be prioritized according to conformance levels, impact on end users, ease and speed of implementation, sections of the site that are in and outside of scope, quick wins or major barriers. For more information please refer to "Prioritizing the Repairs" in Improving the Accessibility of Your Web Site.
Resource: Techniques for WCAG 2.0 provides techniques for meeting the WCAG 2.0 Success Criteria. This document will be updated over time as new techniques and Web technologies evolve.
Based on the changes made when updating your site(s) to WCAG 2.0, review and update any internal Web content development guidance and processes. You will need to refer back to the "Techniques for WCAG 2.0" document on an on going basis because while the Guidelines and Success Criteria of WCAG 2.0 will not change, the techniques may develop together with technologies as well as assistive technologies. This will enable you to evolve your Web site as new technologies evolve and still meet Success Criteria.
The ongoing maintenance is a positive thing, there will be more tips and checks and as technology evolves so will the support and guidance available. It has been written to allow your site to evolve as technologies evolve. As such WCAG 2.0 is flexible, scalable and adaptable.
When the WCAG 2.0 Techniques are updated, WAI will announce this on the home page and via the IG mailing list. To get WAI announcements, you can subscribe to the following: