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Re: Conformance Level Clarification

From: Chris Ridpath <chris.ridpath@utoronto.ca>
Date: Mon, 14 Feb 2005 11:13:27 -0500
Message-ID: <00ef01c512b0$1e1b8030$e29a968e@WILDDOG>
To: "John M Slatin" <john_slatin@austin.utexas.edu>, "WAI WCAG List" <w3c-wai-gl@w3.org>

John wrote:
> We would say that the *delivery unit* conforms at
> level 1 if all level 1 success criteria are satisfied...
>
Yes, thanks for making this clear.

Loretta wrote:
> ...how would you envision level 1 conforming alt text
> differing from level 2 conforming alt text?
>
Level 1 alt text would only be required to meet the level 1 requirements
while level 2 alt text would be required to meet both level 1 and level 2
requirements.

For example, level 1 alt text would be required to be present and describe
the image. Level 2 alt text would require more such as conforming to length
and avoiding placeholder values.

Here is an HTML file that shows the relationship I'm proposing:
http://www.w3.org/WAI/GL/WCAG20/tests/WCAG2-Conformance-Levels.html

There are 3 conformance levels to each success criteria. Some of the
conformance levels may be "not applicable". For example there may not be a
level 1 conformance level for the guideline 3.2 level 3 SC 4 "There are no
extreme changes of context." . Other SC may not have a level 3 conformance
but do have levels 1 and 2 conformance.

This is just a subtle shift from what we have now but it could clear up a
couple of problems.

We keep asking the question "This is good for accessibility but is it really
required to meet a SC?". Now we can answer that it's not required at level 1
but is required at level 2 or perhaps level 3.

This would remove the necessity of looking for other categories such as
"best practice" or "optional". Techniques that would fall into those
categories can now be slotted into one of the 3 levels.

The 3 levels are defined quite well in the WCAG2 and John Slatin has
provided an elaboration that is helpful[1].

Does this look OK to you?

Chris

[1] http://lists.w3.org/Archives/Public/w3c-wai-gl/2005JanMar/0426.html
Received on Monday, 14 February 2005 16:14:57 GMT

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