

[last call] Conformance: levels for success criteria

From: Charles McCathieNevile <chaals@opera.com>
Date: Thu, 22 Jun 2006 06:25:07 -0400
Message-ID: <op.tbjlv5miwxe0ny@researchsft.myhome.westell.com>

Structural/substantive issue

The current levels system for success criteria seems insufficiently  
described, and inappropriate to the needs of developers.

WCAG 20 acknowledges that most criteria are essential in order for some  
people to be able to use some types of web content. It then attempts to  
describe the amount of benefit to usersin general (the difference between  
level 1 and level 2) and the apparent applicability of a technique to the  
web. It appears that the goal is to provide a "reasonable" implementation  
planning tool.

Both of these things are in fact situation-dependent. In some cases, it  
will be easy, in others critical, to apply approaches whose level suggests  
that they are not so important or easy in the general case.

Thus, while providing a signed equivalent of content is extremely  
important in a number of cases, and is occasionally trivially easy (in  
others it is quite expensive), it is perfectly possible that all web  
content claiming triple-A conformance is without signed content.

Similarly, there is no clear technical justification for different  
requirement levels for captioning depending on whether content is  
"live"/"real-time", or pre-recorded. The accesibility result for users who  
rely on captions is exactly the same in both cases. Again, this may be  
easy to implement in some cases, and is very expensive in others, and its  
relative importance will be variable.

In order to assist developers, and policy makers, WCAG should describe the  
imact on users of a particular success criterion being met or not. This  
enables prioritisation based on the actual situation, rather than a  
generalised model situation which will often be an inaccurate  
representation of the case at hand.

I propose that either:
1. the levels be removed, and the information in the currently informative  
"Understanding WCAG" about who benefits be moved to the normtive  
recommendation. Or, as an alternative
2. the specification revert to the WCAG 1.0 priority scheme, rather than  
with the "apparent ease of implementation" clouding the question of their  
relevance to users.



   Charles McCathieNevile, Opera Software: Standards Group
   hablo español  -  je parle français  -  jeg lærer norsk
Received on Thursday, 22 June 2006 10:28:32 UTC
