Accessibility and Usability - Page 5
August 23, 2001
"The power of the Web is in its universality.
Access by everyone regardless of disability is an essential
aspect." Tim Berners-Lee, W3C
Director and inventor of the World Wide Web
A Web site has to be accessible, before it is even
usable. Accessibility refers to the ease with which
either disabled users, or users with non-standard browsing
situations — or even users with typical visual abilities
and the usual browsers — can access the information and
other features of a site. In a sense then, accessibility is an
extension of 'usability', in that a site needs to be accessible
by more than just the CEO at his or her PC on your intranet's T1
or LAN. Consider also blind users, or users at the end of very
slow connections, or users with PDAs, etc. Usability
refers to the ease with which anyone (disabled or not, or with
unusual viewing situations or not) can navigate a site and
achieve the objectives which you have set for it, such as
learning about your product or about an academic topic, or
enjoying the
games and
puzzles in it, etc.
And, beyond that, users should be able to succesfully achieve
subsidiary tasks such as filling in forms to order from your
catalog, or finding contact information in case they want to let
you know about problems with your site (a remarkable number seem
to assume that their sites are perfect since they supply no way
to contact the webmaster!). Your Web site may be wonderful, but
if users find it to be unusable or perceive it to be so then it's
unlikely they'll get far enough to discover just what's so
wonderful about it. The main considerations for usability are:
- do your users possess all the characteristics you assume?
- is the conceptual structure solid, consistent, and intuitive?
- do your users have browsers equipped with the technology you
are depending on?
A page of beautifully colored Netscape layer pull-down menus
won't be much use to the visually impaired non-English speaking
users who favor Lynx, for example. If your target audience
profile excludes such people, fine, but very often Web sites
exclude valid users by default rather than design.
Looky Look!
In my experience, the grossest example of an error in Web site
design, is to emphasise appearance, to the detriment of
accessibility. So many designers seem to feel that aesthetics
outweigh everything else — that a Web page has to look
good, or it's no good. OK, perhaps — but then they go and
design the layout down to the last pixel, fixing the font size so
it can't be enlarged (in some browsers) and run the text out of
the perfectly designed space allocated for it. Never mind that it
might be too small for a few people to actually read. You might
expect that once your page "looks good", people will like your
site. Sad to say, the "looky-look" crowd have done a great deal
of damage to a great many Web sites. The reason is simple (you'd
think): The appearance of a Web site is only one aspect of it. A
great many that "look good" turn out to be unreadable, or hard to
use, or poorly organised. For example, one of the commonest
mistakes is to insist on rigid layout and font size. Not only are
they excluding users with visual impairments, but also users with
viewing situations different from the designer's. You might
assume that, to a first approximation, your target audience
consists of people not entirely dissimilar to yourself. But
beware of treating them as clones. Allow for the possibility that
they might be color-blind, or visually impaired, or they might
not share your mother-tongue, or they might not have the same
kind of computer and monitor as you. Aim for the lowest common
denominator first, and field test your prototypes with as wide a
variety of "guinea-pigs" as you can muster. Later you can add the
'cool' stuff, continually testing for audience response. We
wanted to make
EncycloZine
highly accessibile — not only for disabled users, but also
for users browsing under far less than 'optimal conditions', e.g.
small screens or large viewing distance; text mode browsers, etc.
So we avoided fixed font sizes and image maps, and we put the
navigation menu on the right side rather than the left. A useful
way to see how your page looks to these graphics-challenged users
is to look at it with a text-mode browser such as Lynx.
Growing Hypertrees - Page 4
Design and Architecture of a Content-Rich Web Site
Content First - Page 6
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