Estimates of Accessible Web Sites

Hi everyone,

I recently got email which asked me:

> Just wondering if you folks had any estimates of what percentage of=20
> websites are now accessible.=A0 I know Kynn Bartlett has this info.=A0=20=

> Thank you for any information.

Unfortunately there are no strict figures on this for several reasons:

(1) The term "accessible" is not an absolute; a site may be accessible=20=

to
     to one person with one set of abilities and not accessible to=20
someone
     else.  Lack of alt attributes on an image may not bother a deaf=20
user,
     and lack of transcripts and captions for multimedia may not affect =
a
     dexterity-impaired user.

(2) A site with accessibility problems could range from "difficult to=20
use"
     to "impossible to use" in various sections and for different users,
     making it hard to arrive at a definition of "accessible" that =
covers
     a site.  For example, if there is a single image missing an alt=20
attribute
     on a single page on the site, is that site accessible or=20
inaccessible?

(3) There are several standards for measuring accessibility, including=20=

the
     U.S. government's Section 508, the W3C's WCAG 1.0 in levels A, AA,
     and AAA, "Bobby compliance", and several others.

(4) There is no automatic way to check for accessibility or even for
     compliance with accessibility standards, because property =
evaluating
     accessibility compliance (e.g. "is this alt text a proper=20
alternative
     for this image?") requires human judgment.

(5) There are no reliable methods for taking a sample of sites and
     checking the accessibility of those sites, and extrapolating to the
     rest of the Internet.

This doesn't make it impossible to estimate, but such estimations depend
on who exactly you ask and what assumptions they make to formulate their
answers.

Here are my estimates:

95%+ of Web sites have minor accessibility errors which will make them
      annoying to use for at least one identifiable user group.

75% of Web sites have moderate accessibility errors which
     will make them difficult to use for at least one identifiable
     user group.

50% of Web sites have serious accessibility errors which will make them
     almost impossible to use for at least one identifiable user group.

25% of Web sites have catastrophic accessibility errors which make them
     unusable by at least one identifiable user group.

Where did I get those figures from?  I made them up, based on my
knowledge of Web design and accessibility techniques.  I would say this
is an improvement over 4 years ago, when the numbers would have been:

99%+    Minor accessibility errors;
90%     Moderate accessibility errors;
75%     Serious accessibility errors;
50%     Catastrophic accessibility errors.

What do you all think?  What categories would you use and what=20
percentages
would you set?

--Kynn

--
Kynn Bartlett <kynn(at)idyllmtn.com>                http://kynn.com
Chief Technologist, Idyll Mountain           http://idyllmtn.com
Author, CSS in 24 Hours                  http://cssin24hours.com=

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