WCAG 2.0 Comment Submission

Name: Jason White
Email: jasonw@ariel.its.unimelb.edu.au
Affiliation: none
Document: W2
Item Number: Conformance claims
Part of Item: 
Comment Type: TE
Comment (Including rationale for any proposed change):
The main principle which distinguished level 1 from level 2 success
criteria in the November 2005 working draft, namely that level 1 criteria may
not, whereas level 2 criteria may impose constraints on expression and
presentation of material, has been abandoned in the Last Call draft. No
substitute principle has taken its place. All that the conformance section now
states is that level 1 criteria constitute the minimum, and level 2
requirements offer an enhanced level of accessibility. Level 3 is
distinguished in so far as these criteria may not be applicable to all Web
content.
The lack of a principled distinction between level 1 and level 2 is a
significant weakness of the guidelines as currently drafted, for several
reasons. First, it invites fragmentation of the standard by failing to offer
any defensible ground for the allocation of success criteria to conformance
levels. In contrast, confidence in the integrity of the WCAG 1.0 conformance
scheme, in so far as it worked, is bulstered by the fact that there was a
coherent underlying rationale determining the assignment of priorities to
checkpoints; one was not asked simply to trust the judgment of the working
group in this respect.
Secondly, the WCAG 2.0 levels impose de facto priorities upon success
criteria. The difference between WCAG 1.0 \"priorities\" and WCAG 2.0 \"levels\"
is in name only. Level A conformance, as in WCAG 1.0, still requires
satisfaction of all level 1 items, and correspondingly at level 2 and even at
level 3, where a 50% minimum is arbitrarily imposed. Developers must,
therefore, despite statements in the guidelines to the contrary, treat level 1
items as more important than level 2 items, and level 2 items as more
important than those at level 3. Yet, unlike WCAG 1.0, there is no rationale,
based on impact or any other concept, that determines and justifies these
distinctions among priorities (now called \"levels\"). Implementors, policy
makers and other audiences have no reason to believe that the allocation of
llevels to success criteria is anything better than the outcome of compromise.
This shortcoming of the guidelines needs to be remedied in two steps. First,
the working group should agree upon one or more clear, pertinent and
applicable criteria to distinguish level 1 from level 2 items. Secondly, the
whole document should be reviewed in light of these criteria, re-allocating
success criteria to levels as needed to bring the guidelines into accord with
the chosen principles.
Alternative proposals are provided below. These are not intended to be
exhaustive of the possibilities; other solutions may, and should, also be
considered.
Proposed Change:
Option 1. Reinstate the principle that level 1 success criteria enable user
agents and other tools to adapt the content to meet a wide range of access
requirements, without imposing constraints on the expression or presentation
of the content. Level 2 criteria make the content directly accessible by
regulating expression and presentation as needed to achieve a high degree of
accessibility.
Option 2: Establish \"impact\", as in WCAG 1.0, as the main distinction between
level 1 and level 2 criteria, while acknowledging that this does not apply to
requirements primarily aimed at aiding cognition. For success criteria
primarily related to cognitive disabilities, establish a requirement that
level 1 criteria do not impose constraints on the expression, whether
linguistically, graphically, auditorily etc., of the content. This leads to
the following:
a. At level 1, success criteria eliminate barriers that would otherwise make
it impossible, due to a sensory or physical disability, to access the content.
At level 2, success criteria overcome barriers that would otherwise make it
very difficult, due to a sensory or physical disability, to access the
content. Level 3 criteria further facilitate access (as in WCAG 1.0 priority
3).
b. Level 1 criteria substantially enhance the effectiveness with which people
with cognitive disabilities can access the content, without imposing
constraints on the expression, whether in language, sound or images, of the
information and functionality provided by the content. Level 2 criteria
further facilitate cognition by requiring content to be expressed in ways that
improve its accessibility to people with a variety of cognitive disabilities.
Level 3 criteria are the same as level 2, but place requirements on expression
that cannot be applied to all types of content.
Option 3: Establish a metric of implementation difficulty that is applicable
across technologies and will remain stable over time. This would roughly
correspond to the amount of effort required of an author to implement the
success criteria. Level 1 criteria would demand minimal effort while
substantially overcoming barriers to access, level 2 more effort, and level 3
still further. The measure of \"difficulty\", \"effort\" or whatever, would
provide the basis for making this distinction more precise. I doubt whether
such an idea can be worked out in practice, and I along with other proponents
of enhanced accessibility would object to its introduction into the guidelines
- benefit to people with disabilities, rather than impact on authors, should
 be the primary means of distinguishing among conformance levels. Also, such
 an approach would promote the idea that accessibility is a burden rather
 than an opportunity, clearly an undesirable result.
Option 4: Divide the success criteria in WCAG 2.0 into two categories: (a)
 \"general\": criteria applicable to all types of Web content; and (b)
 \"special\": criteria only applicable to some types of Web content. This
 distinction is already used, albeit roughly, to separate out certain of the
 criteria currently classified as at level 3. Under this proposal, define
 the three conformance levels as follows:
 Level A conformance means that half (50%) of the general success criteria
 are satisfied.
 Level AA conformance means that all of the general success criteria are
 satisfied.
 Level AAA conformance means that all of the general success criteria, and
 all of the special success criteria applicable to the type of content
 involved, are satisfied.
 The \"special\" success criteria would have to be defined and grouped into
 categories to make clear which should be applied to which kinds of content,
 and how the different types of content could be distinguished. Note also
 that additional aids to cognition - controlled vocabularies, symbol systems,
 etc., could be itnroduced as \"special\" criteria in the sense indicated in
 this proposal. They could also be introduced at level 3 under other
 proposals outlined above.
Variations on the above proposals can of course easily be created.
Whatever proposal is chosen, whether one of the above or not, the success
criteria must all be reviewed and, as necessary, reclassified in accordance
with it.

Received on Tuesday, 16 May 2006 09:22:49 UTC

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