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Conformance Level Clarification

From: Chris Ridpath <chris.ridpath@utoronto.ca>
Date: Fri, 11 Feb 2005 10:06:44 -0500
Message-ID: <03ee01c5104b$4d06a580$e29a968e@WILDDOG>
To: "WAI WCAG List" <w3c-wai-gl@w3.org>

During the development of the test suite we've run into some confusion
relating to conformance levels and what is "required" to fulfill a success
criteria. Here's a proposal that tries to clear up some of the confusion.

The guidelines state that for conformance you must meet the success
criteria. You are not required to exceed the success criteria and you can't
come below the success criteria. You've got to "meet" it.

I'll use guideline 1.1 SC 2 as an example. To meet this SC, for HTML
content, images must have alt text. The quality of the alt text is also
taken into account because the SC says it must "convey the same information"
as the image. You can't put garbage in the alt text because that would be
below what is needed to meet the SC. You're not required to enter excellent
alt text because that would exceed the SC. You've just got to put in medium
grade alt text.

Sounds simple but there is a problem - the idea of conformance levels has
been lost. There is no longer any "minimum" level and there is no longer any
"increased accessibility" level. The 3 levels for conformance are now gone.
We can't have minimum level alt text and we can't have "increased level" alt
text. There's no "minimum" level for table markup and no "increased level"
for table markup etc.

The root of the problem is that the conformance level is set by the general
SC. Currently, conformance level is not specific for each technology.

I propose that if a technology specific conformance process exists then it
may set its own conformance levels. In effect, this would allow for 3 levels
of alt text.

Moving the conformance level down to the technology specific conformance
process makes sense. Each technology will be able to determine exactly what
is required for conformance much better than the general SC. This would fix
the problem of tests and techniques getting mapped to inappropriate
conformance levels. We've already got documents that flow from general down
to specific so this is normal.

We need to very clearly state exactly what is required to fulfill the
guidelines at a specific level. Moving the conformance level down to the
specific technology level will allow us to do that.

If there is no technology specific conformance process then the general SC
levels would prevail.

With regard to the HTML test suite - this would allow us to state which
tests were required to fulfill the guidelines at each level. There would be
no "optional" or "advisory" tests. The tests would be sorted according to
priority into the 3 levels as specified by the guidelines. I think we should
use the 3 levels already in the guidelines rather than creating new
categories such as "optional" or "advisory".

Received on Friday, 11 February 2005 15:07:36 UTC

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