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RE: Common failures (was: Common failures and baseline)

From: Gregg Vanderheiden <gv@trace.wisc.edu>
Date: Wed, 24 May 2006 00:21:31 -0500
To: "'Johannes Koch'" <koch@w3development.de>, <w3c-wai-gl@w3.org>
Message-ID: <003701c67ef1$ebc03c20$ee8cfea9@NC6000BAK>

Sorry Johannes, 

I didn't mean your last sentence. I meant the last sentence of the paragraph
above that.  Let me rephrase.   

A common failure causes a failure if the content you are relying on for
conformance contains it.   If it is in an alternate version of the content
(that is in parallel with the accessible version) then the failure (in the
non-accessible version) would not cause the parallel, accessible version to
fail unless it interfered with the accessible version.

RE your second question:  I am not sure what you mean by "the technique must
not interfere with a listed common failure."   I'm not sure what interfering
with a failure means?  Also not sure what it means for a 'test procedure to
fail a success criterion'.  Could you please rephrase your questions?  

Thanks 

Gregg

 -- ------------------------------ 
Gregg C Vanderheiden Ph.D. 
Professor - Ind. Engr. & BioMed Engr.
Director - Trace R & D Center 
University of Wisconsin-Madison 
The Player for my DSS sound file is at http://tinyurl.com/dho6b 
-----Original Message-----
From: w3c-wai-gl-request@w3.org [mailto:w3c-wai-gl-request@w3.org] On Behalf
Of Johannes Koch
Sent: Tuesday, May 23, 2006 3:43 AM
To: w3c-wai-gl@w3.org
Subject: Common failures (was: Common failures and baseline)


> Johannes Koch wrote:
> So the baseline has an influence on the "sufficiency" of a _technique_ to
> _pass_ a SC, but it has no influence on the "sufficiency" of a _failure_
to
> _fail_ a SC?

Gregg Vanderheiden wrote:
> GV: NO.  THAT IS NOT WHAT THE SENTENCE ABOVE SAYS. READ THE LAST SENTENCE.


Let me rephrase my question. The WCAG WG lists some common failures with 
references to the success criteria they are related to. Some author 
writes content in a way described in one of the common failures. Does 
this content fail the related success criteria? Are there any additional 
conditions?

Another point: I think the common failures are expected not to interfere 
with sufficient techniques. So for any part of content and any success 
criterion there cannot be a sufficient technique for which the testing 
procedure results in true and a common failure for which the failure 
condition applies.

In a reply to Tim Boland (May 8, 2006; Message-ID: 
<002701c672a7$85b9d090$ee8cfea9@NC6000BAK>; Subject: RE: Technique 
Designations) you wrote:

<blockquote>
   If they use another technique, then the burden of proof is on them
   should someone ask. It is not a better or worse technique for meeting
   the success criterion. It is just not identified by the working group
   as a technique that is sufficient so it doesn't have that face
   validity.
</blockquote>

So if someone chooses a technique not listed as sufficient in the 
"Understanding WCAG 2.0" document, but which he thinks to be sufficient, 
the technique must not interfere with a listed common failure. Or the 
other way round: If a tester creates a test methodology based on but 
exceeding the listed sufficient techniques and common failures, and 
creates a test procedure for content that he thinks would fail a success 
criterion, this not-listed "common failure" must not interfere with a 
listed sufficient technique.
-- 
Johannes Koch
In te domine speravi; non confundar in aeternum.
                             (Te Deum, 4th cent.)
Received on Wednesday, 24 May 2006 05:21:36 GMT

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