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RE: Conformance Level Clarification

From: John M Slatin <john_slatin@austin.utexas.edu>
Date: Fri, 11 Feb 2005 09:40:42 -0600
Message-ID: <6EED8F7006A883459D4818686BCE3B3B7ADDD2@MAIL01.austin.utexas.edu>
To: "Chris Ridpath" <chris.ridpath@utoronto.ca>, "WAI WCAG List" <w3c-wai-gl@w3.org>

Chris Ridpath wrote:
<blockquote>
...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.

</blockquote>
Chris, we haven't "lost" the idea of multiple levels. It's just that the
criterion you're talking about is at level 1. Currently there are no
Level 2 success criteria for this particular guideline, but there is a
level 3 success criterion.

In the conformance scheme as it currently stands, the idea of levels
doesn't refer to different (increasing) levels of quality-- you're right
that there's no such notion as that Level 3 alt text is *better alt
text* than Level 1 alt text.

What sorts success criteria into different levles is something more like
the following:

Level 11: aimed primarily at supporting assistive technologies and
placing (relatively) few constraints on content, especially on the
default presentation; and the belief that these requirements can
reasonably be applied to all Web content

Level 2: Provides even more support for AT *and* aims at enhancing
"direct accessibility," i.e., enhancing accessibility for people who do
not use assistive technology,  In order to enhance "direct
accessibility" it's often necessary to put constraints on the default
presentation.  Level 2 success criteria can also reasonably be applied
to all Web content, but Level 2 criteria do not have to be met in order
to make a *minimal* conformance claim-- that's Level 1.

Level 3: Even more support for AT *and*  more enhancement of "direct
accessibility"-- and more severe constraints on the default
presentation.  Level 3 success criteria don't necessarily apply to all
Web content, either because they're extremely difficult to achieve or
because they place such tight constraints on the default presentation
that most sites wouldn't be able to meet them.  No one has to meet the
Level 3 success criteria, either.  Or rather, meeting the Level 3
requirements would be an obligation imposed from the outside, for
example by a client who specifies Level 3 when contracting with a vendor
to create a site that has to meet specific needs that are best addressed
at level 3..

Sorry for the longwinded reply, but I hope it helps.

John


"Good design is accessible design." 
John Slatin, Ph.D.
Director, Accessibility Institute
University of Texas at Austin
FAC 248C
1 University Station G9600
Austin, TX 78712
ph 512-495-4288, f 512-495-4524
email jslatin@mail.utexas.edu
web http://www.utexas.edu/research/accessibility/


 



-----Original Message-----
From: w3c-wai-gl-request@w3.org [mailto:w3c-wai-gl-request@w3.org] On
Behalf Of Chris Ridpath
Sent: Friday, February 11, 2005 9:07 am
To: WAI WCAG List
Subject: Conformance Level Clarification



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.

PROPOSAL
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".

Cheers,
Chris
Received on Friday, 11 February 2005 15:40:43 GMT

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