Re: accessibility and usability

On Tue, 30 Nov 2004 09:51:49 +0100, "Barbara de Zoete"
<b_de_zoete (AT) hotmail (DOT) com> wrote:

[F'up set to ciwas-d]

I am getting more and more confused as to the meaning of the words
'accessibility' and 'usability' *in the context of the world wide web*.
What do these two words mean? How do they differ from one another? Where
does the meaning overlap, if it does? Where do they perhaps conflict with
one another, if they do?

You've had quite a lot of good answers, but some points I don't agree
with.

I'd say Accessibility is about being able to access the content of the
site at all (or without excessive difficulty - e.g. tiny fonts) in a
wide variety of situations, both typical *and* atypical.

In practice, typical situations are usually catered for, so the
discussion revolves around less typical situations (especially for
disabled people). But I think it misleading to say accessibility is only
about that. I have indeed on a few occasions met commercial sites that
were not accessible in typical situations - apparently the dezyner had a
huge screen and assumed everyone else did as well.

Usability is about a typical member of the target audience being able to
use the site effectively once he/she has obtained access. Usually this
means being able to find ones way quickly to the required information
and to understand it. Or, almost as important but usually forgotten,
being quickly able to establish that the required information is not to
be found on this site.

Of course for an online shop it means being able to make your purchase
easily. Etc.


So *in any given browsing situation* Accessibility is a prerequisite for
Usability. However it is possible for a site to be poorly accessible
(many people can't read it) but well usable (for those people who are
able to access it).

I actually disagree that appropriate use of language is an Accessibility
issue - that seems to me to clearly fall under Usability - although I
can understand that the authors of the Accessibility Guidelines wanted
to draw attention to it.

Can anyone please explain to someone who is not native speaking, nor
fluent in English?

Not much wrong with your English that I've noticed! I think however that
one can draw an analogy with the distinction between 'verstaan' and
'begrijpen'. (Als je iemand niet kunt verstaan, dan komt er van
begrijpen sowieso niets terecht.)

--
Stephen Poley

http://www.xs4all.nl/~sbpoley/webmatters/