RE: Task Approach to conformance.

  _____  

From: w3c-wai-gl-request@w3.org [mailto:w3c-wai-gl-request@w3.org] On Behalf
Of Gregg Vanderheiden



At the last meeting it was suggested that instead of using web pages or web
units as the basis for making conformance claims that we would use tasks.  

 

[PW] Whether you like the 'idea' or not, why use the term task to replace a
widely understood and already recognised term 'case'. Like your definition
of task, test cases could also have lower level test cases. 

 

[end of comment]

 

This is an interesting idea that both addresses a number of problems we face
and raises a number of new problems.  

 

Because it addresses problems that we have faced and because we have not yet
had a chance to see whether or not the new problems can be addressed I think
it is worth taking time to walk the idea carefully remembering that if it
does not work we can always back off and if it does work it might lead to
some very interesting advances.

 

This email speak neither for nor against the idea.  It is just some thoughts
to get us thinking and exploring the topic.

 

 


Thoughts


 

The first question that strikes me when thinking about basing all the claims
on tasks is "how you would define the word task?".  

In looking at a web page one person could view the whole page as being used
to accomplish a task.  Others could view it as being a collection of many
tasks.  In fact in those cases it probably would come down to being a task
nested in tasks nested in tasks.

 

This nesting of tasks however may not be a problem since the conformance
claim says that all tasks must meet the guidelines.  

Thus if even if you said that the page was an example of triple nested tasks
it would not change the fact that they would all need to be accessible.

 

In fact if we think about it the word "tasks" may be no less testable or
definable than the word "purpose" which we also use in our guidelines.  In
fact, the way we use it may be very similar. 

 

 

Using the "task" as the basis of conformance (or tasks) might solve the
"everything is accessible on my site except the order fulfillment page"
since the PURPOSE or TASK being carried out (and for which the page was
designed) was ordering and you can do that if the fulfillment page is
inaccessible. 

 

We probably would still need to talk about tasks at a URI or range or URIs.
That is, you probably would still have to say that all of the tasks
represented by (or that can be accomplished at) the following URIs would
meet conformance.  Thus the basis for conformance would still be URIs.
Instead of saying web pages or web units however we would talk about the
tasks at that URI.

 

This has the advantage also of blending very nicely with the concept of
equivalent facilitation.  That is if you can carry out all of the tasks at
that URI it does not require that you carry them out in exactly the same
fashion just that it is possible to carry out all of the tasks in a fashion
that meets all of the WCAG guidelines.

 

Concerns

 

*	There will probably be endless arguments about tasks.  What is a
task, what is not a task, whether information presented on a page is a task
or whether tasks are only things you do.  Is music a task, is a movie a
task, etc.  Some of these will be easy to address others might get
contentious.

 

*	There is always the question about whether or not the same task can
be achieved at the same URI.  This is not a different problem I do not
believe than the one we currently have which is whether or not you will be
able to get accessible content at the same URI.

 

*	What if a task spans ten URIs but a conformance claim is only made
on five.  Does the conformance claim only have to cover those tasks which
are fully contained within those five pages or does making a claim on any
page automatically extend the conformance to any task that might be carried
out using that page as a part of the larger set of pages (which go beyond
the conformance claim).  The problem in either direction here is clear.  You
do not want a shopping site to claim conformance to everything but its check
out page and then say well "the only tasks you can do are to window shop."
On the other hand anyone's page might be accessed in the context of a larger
task that they could not possibly be responsible for  (Think "PORTAL" site).

 

Advantages

 

*	It gets to the essence of the page or unit.  That is, the page or
unit was there for a purpose.  If that purpose can be achieved in an
accessible fashion than is that URI accessible?

 

*	It helps to solve the problem between PHP (which generates a bunch
of "pages" from the same URI) and a set of HTML pages which are on different
URIs.  In both cases they allow users to carry out the same task and so they
would be treated the same.

 

 

Just some thoughts to get us thinking. 

 

 

 

 

 


Gregg

------------------------

Gregg C Vanderheiden Ph.D. 
Professor - Depts of Ind. Engr. & BioMed Engr.
Director - Trace R & D Center 
University of Wisconsin-Madison 
< <http://trace.wisc.edu/> http://trace.wisc.edu/> FAX 608/262-8848  

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