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SC Level assignment in WCAG 2.0

From: Bruce Bailey <Bailey@Access-Board.gov>
Date: Tue, 26 Feb 2019 15:59:21 +0000
To: Silver TF <public-silver@w3.org>
Message-ID: <BN6PR22MB0388771B3D81E987343A87A0E37B0@BN6PR22MB0388.namprd22.prod.outlook.com>
On the call today it came up that, in the context of litigation, it was not clear enough to lawyers how success criteria were assigned to the different levels.

The most authoritative explanation is from Understanding Level of Conformance:
http://www.w3.org/TR/UNDERSTANDING-WCAG20/conformance.html#uc-levels-head


See the five bullet list following these two sentences:
The Success Criteria were assigned to one of the three levels of conformance by the working group after taking into consideration a wide range of interacting issues.  Some of the common factors evaluated when setting the level included...

The assignment of levels was the subject of much discussion as the Working Group developed 2.1.  That consensus was posted in the wiki, please see:
http://www.w3.org/WAI/GL/wiki/WCAG_2.1_Success_Criteria#Initial_Suggestion_for_Priority_Level


As part of that effort, I did an analysis (that has *not* been fully vetted by the working group) of the 2.0 against the five bullet points mentioned above.  See the discussion tab of that page:
http://www.w3.org/WAI/GL/wiki/Talk:WCAG_2.1_Success_Criteria


What I found is that:
WCAG 2.0 Level A SC (generally) are two-out-of-three for easy, essential, or invisible -- 21 of 25 Level A SC are characterized this way.
WCAG 2.0 Level AAA SC (generally) are not possible for all content -- 21 of 24 Level AAA SC are characterized this way.
That leaves AA SC (generally) as the remainder.  The more detailed tally is at the bottom of that wiki page:
http://www.w3.org/WAI/GL/wiki/WCAG_2.1_Success_Criteria#Observations









Received on Tuesday, 26 February 2019 15:59:46 UTC

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