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

From: Gregg Vanderheiden <gv@trace.wisc.edu>
Date: Thu, 25 May 2006 23:36:45 -0500
To: "'Johannes Koch'" <koch@w3development.de>, <w3c-wai-gl@w3.org>
Message-ID: <00da01c6807d$ff912f10$ee8cfea9@NC6000BAK>

Thanks Johannes,

This is a very good summary.  In fact

" EARL will provide several "validity levels", e.g. Pass, CannotTell or 
Fail. Applying them to WCAG 2.0, I would say, using a sufficient 
technique results in a Pass, "committing" a common failure results in a 
Fail. Not using a sufficient technique and not committing a common 
failure results in CannotTell."

is so good and concise I think we may use it or something very like it in
the introduction. 

 
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: Wednesday, May 24, 2006 7:08 AM
To: w3c-wai-gl@w3.org
Subject: Re: Common failures (was: Common failures and baseline)


Jason White wrote:

> Suppose my baseline includes XHTML and a version of the RDF 
> specifications currently under development by the Protocols and 
> Formats working group (see their Role Taxonomy and States and 
> Properties, available publicly from the PF home page at
http://www.w3.org/WAI/PF/).
> 
> Now assume that my XHTML fails to provide certain information required 
> by a success criterion, and in doing so it instantiates a "common
failure".

You assume, that not imlementing a listed technique to meet a specific SC is
considered a common failure, right? Why do we need listed commons failures
then?

EARL will provide several "validity levels", e.g. Pass, CannotTell or Fail.
Applying them to WCAG 2.0, I would say, using a sufficient technique results
in a Pass, "committing" a common failure results in a Fail. Not using a
sufficient technique and not committing a common failure results in
CannotTell.

> However, the necessary information is provided in RDF in accordance 
> with the role taxonomy, for which, let us suppose for the sake of the 
> example, there is no listed technique. The content therefore satisfies 
> the success criterion due to the correct implementation of an unlisted 
> technique, using a technology included in the baseline.

Fine, so the user (or the inventor?) of the new technique has to prove the
sufficiency for the SC. Then the result of this technique would be Pass.

> I think the best way of handling this is to say that once you move 
> outside the listed techniques and implement your own, you are 
> responsible for defining a test procedure to establish whether the success
criterion has been met.

But what happens if this new technique uses things that a listed common
failure calls a failure of a SC? Who wins? The new technique or the listed
common failure?

> Ultimately, the success criterion is the determinant of conformance, 
> and I don't think the working group could write its techniques and 
> failures in such a way as to anticipate and handle any technique which 
> an author might come up with, given whatever technologies may be 
> included in the baseline for the content in question.

Of course the WG should only list common failures with technologies which
they have techniques for.
--
Johannes Koch
In te domine speravi; non confundar in aeternum.
                             (Te Deum, 4th cent.)
Received on Friday, 26 May 2006 04:36:52 GMT

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