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Re: Proposal: Simplified presentation of conformance model

From: Charles McCathieNevile <charles@w3.org>
Date: Thu, 28 Dec 2000 08:50:41 -0500 (EST)
To: Ian Jacobs <ij@w3.org>
cc: <w3c-wai-ua@w3.org>
Message-ID: <Pine.LNX.4.30.0012280849130.28849-100000@tux.w3.org>
Looks good to me.

And as I understand the model it has the nice corollary that a claim of
"conformance to UAAG" (without further qualification) means, according to the
spec, what we call triple-A conformance. Which is likely to lead to people
actually thinking about what they are saying a bit more carefully, and
actually getting a bit closer as a result.



On Thu, 28 Dec 2000, Ian Jacobs wrote:


  Don't be scared off by the word "conformance" in the
  subject of this message. I believe this proposal simplifies
  the UAAG 1.0 conformance scheme. It does not stray far from
  what we have already defined, and is, I believe, a clearer

  The model works as follows:

  1) By default, a user agent must satisfy all checkpoints
     in the document in order to conform.

  2) It is possible to reduce the "scope of a claim" [new term]
     in three ways:

     a) Specifying a conformance level. A conformance level is
        a labeled subset of checkpoints.
     b) Specifying one or more content type labels (more labeled
     c) Specifying input modality labels (still more labeled
        subsets). [Note: Input modality labels still a work in

     (These are the three mechanisms we have chosen to
      increase the granularity of conformance claims.)

  3) By default, all checkpoints *within the scope of a claim*
     apply. A checkpoint that is in scope does not apply
     if any of three conditions are met. (Note: We may delete one
     based on some last call comments.)

  Why distinguish a checkpoint that is out of scope
  from one that does not apply?

   - A checkpoint that is out of scope is simply not part of a
   claim. The claim makes *no statement* about whether this
   checkpoint is satisfied or not. It is possible, for example,
   that a user agent would satisfy some, but not all, checkpoints
   for the "video" content type label. The label "video" would not
   appear in the claim, but the user agent would still satisfy
   some of the checkpoints.

   - A checkpoint that doesn't apply *is* part of a claim. The
     claim states explicitly that the user agent *does not*
     satisfy this checkpoint (for if it did, then the checkpoint
     would clearly apply).

  I think it's worthwhile making this distinction. I also think
  that doing so simplifies the presentation of the material and
  the definition of applicable.

  Continuing the model (essentially unchanged):

  4) A well-formed claim must include information about both
     the scope of the claim, and for those checkpoints in scope,
     which ones are not considered to apply. (A well-formed claim
     must also include information about the version of UAAG
     and the date of the claim.)

  5) A claim is valid if:
     a) Well-formed, and
     b) The subject of the claim as a whole satisfies all
        the applicable checkpoints that are in the scope
        of the claim.

  That's the model. Because I do not consider this a substantial
  change from the existing conformance model (only a clarification
  and simplification), I intend to integrate this into the next draft
  for Working Group review.

   - Ian

Charles McCathieNevile    mailto:charles@w3.org    phone: +61 (0) 409 134 136
W3C Web Accessibility Initiative                      http://www.w3.org/WAI
Location: I-cubed, 110 Victoria Street, Carlton VIC 3053, Australia
until 6 January 2001 at:
W3C INRIA, 2004 Route des Lucioles, BP 93, 06902 Sophia Antipolis Cedex, France
Received on Thursday, 28 December 2000 08:50:41 UTC

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