Re: Conformance levels and best practices

On Mon, 15 Sep 2003, Sailesh Panchang wrote:
>
> 1. I believe the words Priority 1, 2 and 3 with their definitions conveyed  that the focus of the checkpoints was on successively increasing levels of   accessibility ... vital -essential-desirable for accessibility, in a way better than that conveyed by the  terms coreand extended. Admittedly, there   are different perspectives on the priority levels assigned to some checkpoints in WCAG1. But a P3 checkpoint  enhances accessibility and therefore usability and shows the way ahead as is intended for "best practices".  So why not  stick with the terms P1, P2 and P3... it will also be   "backward compatible"... Goal 6 for WCAG2 in requirements doc. The required success criteria should be  categorized as  P1 or P2 or P3.

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.

To summarize, the WCAG 1.0 priorities were built on the idea that
adherence to certain design principles would, respectively, remove
barriers that precluded access to the content by identifiable groups of
users (P1), barriers that made it very difficult for certain groups to
access the content (P2) and difficulties that reduced the effectiveness
with which the content could be accessed. This explanation, I should
emphasize, is only my hasty attempt to give an informal summary of the 1.0
definitions, and should in no way be interpreted as supplementing,
clarifying or replacing the formal definitions in the 1.0 document.

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.

Received on Tuesday, 16 September 2003 00:07:10 UTC