Action-827 Updated Definition of Levels

Greg raised some excellent points in his email of
http://lists.w3.org/Archives/Public/w3c-wai-ua/2013AprJun/0039.html

I added a list of the factors we considered (mostly from the Priorities 
spreadsheet, but some from discussions we have had)

I made several attempts to include all the factors in the levels but 
gave it up as too complex, and decided to put more emphasis on the 
balance between the two sides.

Here is my new proposal:

UAAG conformance levels (A, AA, AAA) provide a path for user agent 
developers to improve their product over time and to prioritize new 
features to develop. Factors that were considered in the process of 
assigning priorities include:
* severity of impact to the user
* inconvenience to other groups of users with disabilities
* commonality of present implementations
* difficulty of implementation (from deterministic to inferential)
* difficulty of implementation (from minor change to creation of a new 
sub-system)

UAAG conformance levels attempt to balance the needs of people with 
disabilities with the difficulty the user agent developer could 
experience in meeting that need. There are many different types of 
disabilities and different types of user agents, so the UAAG level 
assigned to a success criterion may not precisely match the definition 
of the level in all circumstances. To avoid over-complication, the 
various combinations of factors were separated into 3 levels:

Level A success criteria represent needs where different groups of 
people with disabilities are blocked from receiving information or 
accomplishing a task and/or the solutions to those needs are relatively 
minor for developers to solve or the solutions are common in the 
marketplace. In some cases, extensions or addons to popular browsers 
provide solutions.

Level AA represents needs where people with disabilities have difficulty 
accessing information or accomplishing a task (including tasks causing 
excessive fatigue), and where the solutions may be more difficult to 
implement or requires developing a new subsystem for the product.

Level AAA represents needs where the solution improves accessibility for 
specific groups or reduces fatigue to accomplish tasks, but the solution 
is challenging to solve, requiring a major effort or development of 
intelligent algorithms.

Received on Thursday, 9 May 2013 16:21:49 UTC