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RE: Validity as a technique

From: John M Slatin <john_slatin@austin.utexas.edu>
Date: Mon, 7 Nov 2005 10:05:08 -0600
Message-ID: <6EED8F7006A883459D4818686BCE3B3B0268A4F0@MAIL01.austin.utexas.edu>
To: "Gregg Vanderheiden" <gv@trace.wisc.edu>, "Yvette Hoitink" <y.p.hoitink@heritas.nl>, <w3c-wai-gl@w3.org>

Gregg responded to Yvette's suggestion:

<blockquote>
I think this is good approach.

However note that we do not specify anything as necessary - just as
sufficient.   So necessary but not sufficient is not possible in the
Guide
Doc (which cannot specify new requirements).
</blockquote>

I agree that the *phrase* "necessary but not sufficient" can't be used
in the Guide doc. But I think there are places where we list
*combinations* of techniques as sufficient, e.g.,

Using Technique X *and* Using Technique Y.

So "Validating code" could be the Technique Y for those cases where it's
needed to support the "programmatically determined" requirement.

John

"Good design is accessible design."

Dr. John M. Slatin, Director 
Accessibility Institute
University of Texas at Austin 
FAC 248C 
1 University Station G9600 
Austin, TX 78712 
ph 512-495-4288, fax 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 Gregg Vanderheiden
Sent: Monday, November 07, 2005 9:51 AM
To: 'Yvette Hoitink'; w3c-wai-gl@w3.org
Subject: RE: Validity as a technique



I think this is good approach.

However note that we do not specify anything as necessary - just as
sufficient.   So necessary but not sufficient is not possible in the
Guide
Doc (which cannot specify new requirements).

However, if validity is required to programmatically determine something
then it would already be covered.   

Several people have made this point - and it seems to indicate that
validity testing would be a very good tool to use in achieving the goal
of 'programmatically determined'. 
 

Gregg

 -- ------------------------------ 
Gregg C Vanderheiden Ph.D. 
Professor - Ind. Engr. & BioMed Engr.
Director - Trace R & D Center 
University of Wisconsin-Madison 


-----Original Message-----
From: w3c-wai-gl-request@w3.org [mailto:w3c-wai-gl-request@w3.org] On
Behalf Of Yvette Hoitink
Sent: Monday, November 07, 2005 9:43 AM
To: w3c-wai-gl@w3.org
Subject: Validity as a technique


Hello everyone,

I'm trying to find some middle ground on the topic of the requirement
for validity in WCAG. One of the many arguments for requiring validity
at level 1 had to do with the fact that otherwise, some of our other
requirements wouldn't be met because you can't programmatically
determine things if there are syntax errors. That made me think: isn't
validity a necessary but not sufficient technique for some of our
guidelines? 

I propose to delete the requirement for validity from our guideines and
instead list it as a necessary but not sufficient technique for all the
success criteria that require something can be 'programmatically
determined'. I think this would solve many of the problems:

* We do not require it in the normative section (the guidelines), which
prevents legal actions against websites that are accessible but do not
validate because they used an attribute that isn't defined in the specs.

* We limit our guidelines to things that clearly cause accessibility
problems when violated, which makes the document more believable. Since
validity falls into the category of 'how to do this' this is put in the
techniques. 

* We stimulate using other W3C standards and emphasize the importance of
validity without using WCAG as a platform for other agendas such as the
promotion of valid code. 

Any thoughts?

Yvette Hoitink
Heritas, Enschede, the Netherlands
E-mail: y.p.hoitink@heritas.nl
WWW: http://www.heritas.nl 
Received on Monday, 7 November 2005 16:05:13 GMT

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