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

From: Johannes Koch <koch@w3development.de>
Date: Wed, 24 May 2006 14:08:29 +0200
Message-ID: <44744CBD.2040705@w3development.de>
To: w3c-wai-gl@w3.org

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 Wednesday, 24 May 2006 12:08:52 UTC

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