[html4all.org] changing definitions

[Jason White]

On Thu, Aug 23, 2007 at 02:08:55AM -0500, Robert Burns wrote:
 
> Wikipedia define use-case[2] as:
> A use case is a technique used in software and systems engineering to  
> capture the functional requirements of a system. Use cases describe  
> the interaction between a primary actor?the initiator of the  
> interaction?and the system itself, represented as a sequence of  
> simple steps. Actors are something or someone which exist outside the  
> system under study, and who (or which) take part in a sequence of  
> activities in a dialogue with the system, to achieve some goal: they  
> may be end users, other systems, or hardware devices. Each use case  
> is a complete series of events, from the point of view of the actor.[1]

This is a reasonable definition of the concept. One of the points of
disagreement implicit in much of the discussion on the mailing list is over
the kinds of use cases that need to be demonstrated in order for a feature to
be considered worthwhile for inclusion in HTML. An excellent example of this
is the debate surrounding implicit vs. explicit association of media objects
with alternatives, which rapidly turned into a dispute as to whether the
proposed use cases were really use cases at all, and whether they could be
debunked or dismissed as inadequate.

Part of the problem here is a systematic under-valuing, on the part of those
who doubt such use cases, of the expertise, experience and knowledge of
accessibility specialists, leading to the "evangelism isn't enough" slogan
that has been repeated a number of times. I think there is also an assumption
that accessibility doesn't require equality of user interfaces - that it is
acceptable for alternative renderings to be inferior to the visual interface,
as when locating and following a link to an alternative is supposed to be a
satisfactory substitute for having audio or video content rendered
automatically as part of the Web page.

One of the striking findings of the Disability Rights Commission (UK) empirical
study of accessibility, carried out by Helen Petrie et al., was the additional
time taken by users with disabilities (especially those who were blind or
vision-impaired) to complete their tasks, even where the latter were
ultimately carried out successfully. This suggests to me that any improvements
which can be made to optimize the user interfaces provided by assistive
technologies, have the potential to contribute toward reducing the time
required to complete tasks, while increasing the success rate (which, again,
was remarkably low even on sites that met accessibility guidelines). Improved
user interfaces require improved semantics in the markup, which is why the Web
needs to head firmly in that direction.