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Re: Verification and validation of accessibility

From: Charles McCathieNevile <charles@w3.org>
Date: Tue, 13 Apr 1999 22:00:37 -0400 (EDT)
To: Jason White <jasonw@ariel.ucs.unimelb.EDU.AU>
cc: WAI Markup Guidelines <w3c-wai-gl@w3.org>
Message-ID: <Pine.LNX.4.10.9904132157540.23704-100000@tux.w3.org>
My personal opinion is that we should provide, as informative assistance,
some methods of verification. The checklist, as it is composed of the
checkpoints in the document, and is a complete set, is the one part of
this which should be normative.

I don't think we should attempt to prioritise the various methods, as the
appropriateness of a given test is extremely dependent on the needs and
abilities of the person who requires the test. We could usefully give some
ideas about teh various strengths and weaknesses in each approach, but
that itself must be done very carefully.

Charles McCN

On Wed, 14 Apr 1999, Jason White wrote:

  In an appendix to the Guidelines, various techniques for validating and
  verifying the accessibility of documents are proposed. These range from
  the use of validation tools, to displaying the document with user agents
  that have different capabilities. Should these techniques be prioritised?
  The existing list seems rather lengthy and, while I would not suggest
  omitting any of the items, it would seem reasonable to provide content
  developers with guidance as to which approaches have proved most effective
  practice as means of detecting coding and design shortcomings that hinder
  access. However, it can also be argued that quick solutions such as
  evaluation tools should not be used as substitutes for the longer but also
  more revealing process of examining different renderings of documents by
  various user agents, under diverse conditions. This point suggests that an
  attempt to prioritise the evaluation and verification techniques would
  lead to a contest between (1) speed and efficiency of application through
  validation tools; and (2) comprehensiveness of assessment, via more
  reliable methods of human checking.
  
  Should we simply leave these considerations to the discretion of content
  developers as in the Proposed Recommendation, or seek to classify the
  verification techniques, perhaps even indicating which should be tried
  first, or which should receive first priority?
  
  
  

--Charles McCathieNevile            mailto:charles@w3.org
phone: +1 617 258 0992   http://www.w3.org/People/Charles
W3C Web Accessibility Initiative    http://www.w3.org/WAI
MIT/LCS  -  545 Technology sq., Cambridge MA, 02139,  USA
Received on Tuesday, 13 April 1999 22:00:45 GMT

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