RE: working definition of baseline

This is great, Loretta.  Very useful!

Some responses inline, preceded by "JS:"


-----Original Message-----
From: [] On
Behalf Of
Sent: Friday, May 06, 2005 2:27 pm
Subject: Re: working definition of baseline

What are we trying to communicate here:

1. WCAG needs authors to use technologies for which accessible user 
agents are available to the users. We refer to such a set of 
technologies as a baseline (and we need a better word than baseline 
for such a set of technologies).
JS: I agree, but would like to unpack "accessible user agents" a bit. We
want authors to use technologies for which there are user agents that
(a) render content produced by those technologies in an accessible way
and (b) are accessible to users with disabilities. 

2. Because the properties of user agents change over time, and because 
the set of user agents available to users differs for different 
populations of users, WCAG cannot define the baseline in the normative 
part of the guidelines.
JS: Agreed.

3. A baseline can be defined for a given population of users at a 
given point in time, that is, it is possible to analyze the 
accessibility properties of user agents and to assess what user agents 
should be available to a set of users and come up with the list of 
technologies supported by accessible user agents. 
JS: That phrase "should be available" jumped out at me.Authors can't
assume that something "should" be available. They have to be able to
assume that the Something either is or is not available. The assumptions
may be constrained by government or coprporate policy or in some other
way, or the author may be in a position to know for certain that a given
technology *is* available (e.g., when developing an intranet for a
specific client who has spelled out system requirements, etc.). If there
isn't a clear policy and there isn't certain knowledge, then the author
has to assume that only the most basic technologies are supported by and
active in the user agent.

4. A WCAG conformance claim is always relative to an identified 
baseline. Implicit in that claim is the assumption that the identified 
baseline correctly reflects the audience of the web content at the 
time of the claim, that is, that the analysis of user agents in step 3 
was correct at the time of the claim.
JS: Yes. This is very important.

5. An author can use technologies outside the identified baseline as 
long as the use of those technologies degrades gracefully to the 
baseline with no loss of information or functionality.
JS: Yes.

Is this correct? Have I misunderstood something or missed something 
that needs to be communicated to readers of WCAG?
JS: It's very clear and I think it will be very helpful.  My comments
are intended as clarifications-- and I hope they are!<grin>


Received on Friday, 6 May 2005 19:48:35 UTC