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OTACS 2 and the WCAG 2.0 priority 1 definition

From: Jason White <jasonw@ariel.ucs.unimelb.edu.au>
Date: Sat, 27 Oct 2001 16:51:24 +1000
Message-ID: <15322.22892.691153.848512@gargle.gargle.HOWL>
To: Web Content Guidelines <w3c-wai-gl@w3.org>
Upon analysis, I think OTACS 2 and the WCAG 1.0 priority 1 definition
are, in effect, very similar, but OTACS 2 is less restrictive.

In WCAG 1.0, priority 1 checkpoints were those which removed barriers
that would otherwise make it absolutely impossible for an identifiable
group of users to access the content. In applying this definition, the
current state of technology (not actual implementations, but rather
what was possible in principle using known algorithms and approaches)
was taken into account. Thus, if certain functionality required to
make the content accessible could be supplied by software, the
corresponding checkpoint did not count as priority 1.

Furthermore, the notion of what it meant for a user to "access the
content" was somewhat narrow. It was assumed for example that loss of
structure did not render the content completely inaccessible, but
merely difficult to use.

OTACS 2 is similar to the WCAG 1.0 priority 1 definition, but it
involves a less restrictive concept of accessibility. It assumes that
the user must be provided with means of reading, navigating and
interacting with the content effectively. The checkpoints in the
minimum set are those which, if satisfied, eliminate barriers that
would otherwise prevent an identifiable group of users, with the aid
of client-side software, from reading, understanding, navigating and
interacting with the content.

This formulation is equivalent to OTACS
2, but it is written from the user's rather than from the author's
perspective. Essentially, the user's ability to read the content,
traverse and appreciate its structure, or provide input via a user
interface, will necessarily be restricted in ways that can't be
rectified by client-side software unless the checkpoints in the
minimum set have been met.

Thus I think OTACS 2 and the foregoing equivalent are
broader than WCAG 1.0 priority 1, in that they do not take the
restrictive approach to accessibility which the latter implies.

I can't think of a good, short label that can be attached to my
alternative formulation, unfortunately. Perhaps it should be called
the FILU principle: "functionality is lost unless", where
"functionality" means the user's ability to perceive, understand and
Received on Saturday, 27 October 2001 02:51:31 UTC

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