RE: SC Level assignment in WCAG 2.0

Definitely not hard and fast rules for the level assignments, but I was surprised how distinct the patterns are after-the-fact with the benefit-of-hindsight.
The did-it-require-AT question was not something I thought to capture in my analysis.
The impacting the look and feel of the website is very much reflected in that table, under the column heading “invisible”.
Of course, the SC that are invisible are also going to be things that tend to require AT to get the benefits.

From: David MacDonald <david100@sympatico.ca>
Sent: Thursday, February 28, 2019 6:08 AM
To: Bruce Bailey <Bailey@Access-Board.gov>
Cc: Silver TF <public-silver@w3.org>
Subject: Re: SC Level assignment in WCAG 2.0

Two additional factors that went into the decision of what level to choose were:

- Did it require AT? The Level A SCs generally didn't require a user to purchase Assistive Technology (i.e. magnification)
- Did it impact the look or feel of the website, and cause redesign? Level A generally doesn't require a change to the look or feel of the site.

We've always been careful not to create hard and fast rules about when something was Level A or AA and have stuck with "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."


Cheers,
David MacDonald



CanAdapt Solutions Inc.

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On Tue, Feb 26, 2019 at 10:59 AM Bruce Bailey <Bailey@access-board.gov<mailto:Bailey@access-board.gov>> wrote:
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<https://na01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.w3.org%2FTR%2FUNDERSTANDING-WCAG20%2Fconformance.html%23uc-levels-head&data=02%7C01%7CBailey%40access-board.gov%7C8ac19d7d3ea145a31b3f08d69d6d12d5%7Cfc6093f5e55e4f93b2cf26d0822201c9%7C0%7C0%7C636869489154456892&sdata=IbsNa9PyMbsJYX0NkG0p1lGPaQXxHd%2FsZlbIIms60NA%3D&reserved=0>

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<https://na01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.w3.org%2FWAI%2FGL%2Fwiki%2FWCAG_2.1_Success_Criteria%23Initial_Suggestion_for_Priority_Level&data=02%7C01%7CBailey%40access-board.gov%7C8ac19d7d3ea145a31b3f08d69d6d12d5%7Cfc6093f5e55e4f93b2cf26d0822201c9%7C0%7C0%7C636869489154466896&sdata=ecasUu8tZ6yb3s6SN6r9RDeOXYtfqJZu379ukd4Kw%2Bw%3D&reserved=0>

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<https://na01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.w3.org%2FWAI%2FGL%2Fwiki%2FTalk%3AWCAG_2.1_Success_Criteria&data=02%7C01%7CBailey%40access-board.gov%7C8ac19d7d3ea145a31b3f08d69d6d12d5%7Cfc6093f5e55e4f93b2cf26d0822201c9%7C0%7C0%7C636869489154466896&sdata=kucNOUa2vjYurx4jE9duK1by2kpzP1v9hruZSxVOIIY%3D&reserved=0>

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<https://na01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.w3.org%2FWAI%2FGL%2Fwiki%2FWCAG_2.1_Success_Criteria%23Observations&data=02%7C01%7CBailey%40access-board.gov%7C8ac19d7d3ea145a31b3f08d69d6d12d5%7Cfc6093f5e55e4f93b2cf26d0822201c9%7C0%7C0%7C636869489154476905&sdata=MT30KoG4TUQBZA%2F85xsWqhpS6gqygdc232t2I630Uzo%3D&reserved=0>