W3C home > Mailing lists > Public > public-comments-wcag20@w3.org > June 2007

Re: Your comments on WCAG 2.0 Last Call Draft of April 2006

From: Charles McCathieNevile <chaals@opera.com>
Date: Mon, 11 Jun 2007 13:06:21 +0200
To: "Loretta Guarino Reid" <lorettaguarino@google.com>
Cc: public-comments-WCAG20@w3.org
Message-ID: <op.ttq7svocwxe0ny@widsith.local>

On Fri, 18 May 2007 01:28:47 +0200, Loretta Guarino Reid  
<lorettaguarino@google.com> wrote:

> ----------------------------------------------------------
> Comment 2:
> Source:  
> http://www.w3.org/mid/op.tbjlv5miwxe0ny@researchsft.myhome.westell.com
> (Issue ID: LC-1303)
> Structural/substantive issue
> The current levels system for success criteria seems insufficiently
> described, and inappropriate to the needs of developers.
> WCAG 20 acknowledges that most criteria are essential in order for
> some people to be able to use some types of web content. It then
> attempts to describe the amount of benefit to usersin general (the
> difference between level 1 and level 2) and the apparent applicability
> of a technique to the web. It appears that the goal is to provide a
> "reasonable" implementation planning tool.
> Both of these things are in fact situation-dependent. In some cases,
> it will be easy, in others critical, to apply approaches whose level
> suggests that they are not so important or easy in the general case.
> Thus, while providing a signed equivalent of content is extremely
> important in a number of cases, and is occasionally trivially easy (in
> others it is quite expensive), it is perfectly possible that all web
> content claiming triple-A conformance is without signed content.
> Similarly, there is no clear technical justification for different
> requirement levels for captioning depending on whether content is
> "live"/"real-time", or pre-recorded. The accesibility result for users
> who rely on captions is exactly the same in both cases. Again, this
> may be easy to implement in some cases, and is very expensive in
> others, and its relative importance will be variable.
> In order to assist developers, and policy makers, WCAG should describe
> the imact on users of a particular success criterion being met or not.
> This enables prioritisation based on the actual situation, rather than
> a generalised model situation which will often be an inaccurate
> representation of the case at hand.
> I propose that either:
> 1. the levels be removed, and the information in the currently
> informative "Understanding WCAG" about who benefits be moved to the
> normtive recommendation. Or, as an alternative
> 2. the specification revert to the WCAG 1.0 priority scheme, rather
> than with the "apparent ease of implementation" clouding the question
> of their relevance to users.
> cheers
> Chaals
> ----------------------------
> Response from Working Group:
> ----------------------------
> The description of conformance levels in WCAG 2 has been rewritten to
> clarify the differences (see
> http://www.w3.org/TR/2007/WD-WCAG20-20070517/#overview-levels ):
> The word "levels" does not mean that some success criteria are more
> important than others. Each success criterion in WCAG 2.0 is essential
> to some users, and the levels build upon each other. However, even
> content that conforms at AAA (triple-A) may not be fully accessible to
> every person with a disability.
> *In general, Level A success criteria achieve accessibility by
> supporting assistive technology while putting the fewest possible
> limits on presentation. Thus people with a wide range of disabilities
> using a wide range of assistive technologies, from voice input and
> eye-tracking devices to screen readers and screen magnifiers, are able
> to access content in different ways. In other words, Level A success
> criteria support the ability of both mainstream and specialized user
> agents to adapt content to formats that meet their users' needs.
> *The success criteria in Level AA provide additional support for
> assistive technology. At the same time, they also support direct
> access to content by the many people who use conventional user agents
> without assistive technology. In general, Level AA success criteria
> place more limits on visual presentation and other aspects of content
> than the success criteria in Level A.
> *Level AAA success criteria increase both direct access and access
> through assistive technology. They place tighter limits on both
> presentation and content.
> ----------------------------------------------------------

The conditions seem to be ambiguous with respect to their impact on people  
with disabilities, and heavily based on the irrelevant (to accessibility)  
question of how much impact it might have on the ability to use arbitrary  
presentation and design. They certainly don't provide a clear measure of  
the impact on people with disabilities, even whenn combined with the  
informative "Understanding ..." document, which means that this  
specification is not very helpful for determining accessibility except in  
the context of an arbitrary requirement that any possible means of  
presentation is acceptable.

The only rational interpretation is therefore that the working group has  
tried to assess some measure of "reasonable effort" or "cost/benefit"  
without explaining this. Obviously, it is more dificult to caption live  
multimedia than pre-recorded content from a library in some cases although  
it seems perfectly feasible for most major US television networks to do  
it, since they do both kinds of content in practice. Therefore a different  
priority based apparently only on this consideration represents the  
working group stepping far beyond the question of accessibility, and into  
making guesses about content production which are both inappropriate and  
outside the scope of their expertise.

I consider the issue raised totally unsatisfied by the response, and will  
continue to raise it, if required as a formal objection.



   Charles McCathieNevile, Opera Software: Standards Group
   hablo español  -  je parle français  -  jeg lærer norsk
chaals@opera.com  Catch up: Speed Dial  http://opera.com
Received on Monday, 11 June 2007 11:06:35 UTC

This archive was generated by hypermail 2.4.0 : Friday, 17 January 2020 19:14:44 UTC