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Checkpoint on testability

From: Leonard R. Kasday <kasday@acm.org>
Date: Thu, 21 Dec 2000 17:16:46 -0500
Message-Id: <4.3.2.7.2.20001221163710.00e27520@pop3.concentric.net>
To: "w3c-wai-gl@w3.org" <w3c-wai-gl@w3.org>
Per my action item from last call here's a first cut at a new guideline:

Guideline X.  Design for so that testability can most easily be verified.
Pages should be designed to minimize amount of human effort needed to 
confirm accessibility.

checkpoint x.1
Specify in machine readable form specifications against which machine 
verification may be preformed.
Example: in HTML include the DOCTYPE.

checkpoint x.2
Avoid use of alternative version of content that requires human effort to 
verify.
Example: Avoid when possible manually created images of text; use styled 
text instead.  Note that automated generation of images of text are allowed 
per checkpoint x.3

checkpoint x.3
When alternative versions of content are created, create them automatically 
when possible.
Example: A program that automatically converts text to images

checkpoint x.4
When alternative content is created manually, make specific correspondence 
between content and its particular alternative.
Negative Example:  A manually created alternative text-only site in which 
information is distributed differently among ithe pages.  Validating the 
equivalence of such a manually created site is very labor intensive.
Positive Example: Image and ALT text.  It's simple for a tool to present 
image and ALT tag to user for comparison (e.g. in A-Prompt and in the Wave)
Positive Example: Content provided by Object tag and nested object tag.
Positive Example: Two sites created from common data through different 
transformations, PROVIDED that the transformation rules are publically 
visible for validation.

checkpoint x.5
When possible, Use only styles linked consistently to particular semantic 
objects.
Example: CSS rule that makes all Headings a particular style.
Negative Example: CSS rule linked to class.  Current CSS has no way to 
expose class semantics to user agent, so it takes human judgment to decide 
if the class is simply decorative, which is harmless, or is carrying 
information unavailable to user agents.
--
Leonard R. Kasday, Ph.D.
Institute on Disabilities/UAP and Dept. of Electrical Engineering at Temple 
University
(215) 204-2247 (voice)                 (800) 750-7428 (TTY)
http://astro.temple.edu/~kasday         mailto:kasday@acm.org

Chair, W3C Web Accessibility Initiative Evaluation and Repair Tools Group
http://www.w3.org/WAI/ER/IG/

The WAVE web page accessibility evaluation assistant: 
http://www.temple.edu/inst_disabilities/piat/wave/
Received on Thursday, 21 December 2000 17:16:56 GMT

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