Re: Conformance levels and core /extended

Message1. Well then, the  proposed conformance system (claim to core / extended / core+ etc) is no measure of accessibility at all. 
I believe that a system that measures conformance to accessibility  guidelines  must: 
- consider  impact on usability  for user population  being served by the accessibility guidelines by  
- assessing compliance against checkpoints    (and accessibility guidelines) applicable to a page / site / application.
   
I fully  agree with John's statement that the distinction between core and extended  is  developer-centered" as   "Core do not make you change the document  visually - just mark it up or add hidden text (or audio) "equivalents"". (I recognize that some content that is meant to give a "sensory experience" (recent list discussions) cannot really be made  "accessible".). If some "extended checkpoints are also important", then a website that claims only "core"  might still have  many serious accessibility-related flaws. How does it matter to me as a website user, if a website claims "core" level? What does it tell me about the  accessibility level of the site? For instance say  of the important-to-accessibility checkpoints applicable to a site, only 25 percent   belong to the core group while 75 percent belong to the extended group. 

2. So the core checkpoints might probably be relatively easy and quick in some instances to make content accessible. 
  How is  the process used to make Web content accessible relevant to a conformance to an accessibility claim? 
How does it matter if the developer needs to spend three minutes or three hours to make some content accessible  as per the organizations adopted accessibility policy?
If the developers realize that the technology or design adopted does not support the  required accessibility level and need to  make drastic  changes in order to gain compliance, then they may be required to do so.
An analogy: how is the time/process/cost  needed to build a bridge   relevant to a statement on the "safety level" of the bridge?

We should not drift away from the objective of measuring accessibility to user population served by the guidelines. 
3. And this measure must  definitely  consider importance of  the checkpoints  with respect to accessibility. For instance absence of  a text descriptor for an  image   that is important to understanding content is a serious violation. But if  every link begins with the words "Link to" instead of the key/action word in  the link, it may make navigation inefficient(but not inaccessible) for the   screen reader user trying to  navigate using a list of links pulled up by  the access technology used. This will be a less serious accessibility  violationn.
  
So I am afraid I am again proposing the  conformance system used for WCAG 1.0. 

4. By the way, the philosophy underlying core / extended is radically differennt but what are the serious weaknesses / limitations or disadvantages of P1/P2/P3 system? Is it so vital to adopt a new conformance system to measure accessibility? Why not proceed with a workable system already in use, perhaps with some tweeking? The P1/P2/P3 system has been used by other W3C guidelines including the  one that measures the QA process for creating W3C guidelines.


Please do not interpret this as resistance to change, but I  want a good reason to subscribe to the _new accessibility_ conformance system being advocated by WCAG 2.0.
Thanks for your time and  indulgence,
Sailesh Panchang, Senior Accessibility Engineer
Deque Systems, Reston, Virginia 20191
Tel 703-225-0380 (ext 105)
  On Thursday, September 18, 2003 10:09 am Gregg Vanderheiden  wrote:
  In 1.0 it was  priority 1,2,3 based on user need

  In 2.0   the dividing line between core and extended is not user need but whether it involved constraining the content or presentation.
  In 2.0   the dividing line between core and extended is not user need but whether it involved constraining the content or presentation. 
  Core do not make you change the document visually - just mark it up or add hidden text (or audio) equivalents.

  There are many extended checkpoints that are VERY important.

  It is true that all the core checkpoints are important.  But it is not true that all the important checkpoints are core. 

  On  Thursday, September 18, 2003 11:53 AM  John M Slatin  wrote

  "I still have some fundamental concerns  about the idea that CORE checkpoints are (or should be) those that don't require content developers and designers to change the  efault visual presentation.
  ...
  I'm concerned that the current criteria for distinguishing "core" from "extended" is *developer*-centered.  
  ...
  I would argue, then, that extended checkpoints that we agree are truly important to meeting the needs of users with disabilities should go into the "core.  

  John"
On Tuesday, September 16, 2003 12:07 AM
Jason White
wrote

Subject: Re: Conformance levels and best practices

"Others have argued, however, that precisely because the conceptions of conformance levels have changed so radically between WCAG 1.0 and WCAG
2.0, the same terms (Priority 1, Priority 2 and Priority 3) should not be
carried forward into the 2.0 document, as this would create confusion for those who are already acquainted with the 1.0 conformance structure and its definitions.

In developing WCAG 2.0, the distinctions underpinning the 1.0 priority definitions were subjected to detailed, critical scrutiny, with the result
that the working group decided they were no longer tenable for purposes of
the 2.0 document, and that a new set of distinctions was needed to classify checkpoints and success criteria in constructing the 2.0
conformance scheme. The argument for new terminology, then, is that unless
different terms were used, readers acquainted with 1.0 would construe 2.0
as following the same, or a similar, system of priorities and conformance levels as WCAG 1.0, and would make policy decisions and claims about
accessibility on that erroneous, but tempting, presupposition. The new
terminology is supposed to signal the fact that the 2.0 categories of core and extended are very different from the 1.0 priorities, and that the
impossible/difficult/easier approach worked out in the 1.0 conformance
scheme does not apply to 2.0."

My purpose in stating these arguments is not to defend them, though I do
happen to find them persuasive, but to attempt to recapitulate the reasons
which led the working group to the conclusion that new terminology was
needed and that retention of the old terminology would do more harm than
good.

Comments, counter-arguments and proposals are, of course, most welcome. If
anyone is dissatisfied with the working group's prior decisions on this
matter, the issue should be re-opened in the context of our ongoing
conformance discussion.
"