W3C home > Mailing lists > Public > public-html@w3.org > February 2010

ISSUE-30 counter-proposal

From: Ian Hickson <ian@hixie.ch>
Date: Sun, 14 Feb 2010 08:54:07 +0000 (UTC)
To: public-html@w3.org
Message-ID: <Pine.LNX.4.64.1002140850570.29483@ps20323.dreamhostps.com>

Here's a counter-proposal for ISSUE-30:

== Summary ==

The longdesc="" attribute does not improve accessibility in practice and 
should not be included in the language.

== Rationale ==

Several studies have been performed. They have shown that:

* The longdesc="" attribute is extremely rarely used (on the order of 0.1% 
in one study). [http://blog.whatwg.org/the-longdesc-lottery]
* When used, longdesc="" is extremely rarely used correctly (over 99% were 
incorrect in a study that only caught the most obvious errors 
[http://blog.whatwg.org/the-longdesc-lottery]; the correct values were 
below the threshold of statistical significance on another study that 
examined each longdesc="" by hand 
[http://wiki.whatwg.org/wiki/Longdesc_usage]).
* Most users (more than 90%) don't want the interaction model that 
longdesc="" implies. 
[http://webaim.org/projects/screenreadersurvey2/#images]
* Users that try to use longdesc="" find it doesn't work ("Who uses this 
kind of thing? In my experience [...] it just didn't work. There was no 
description.") [http://www.cfit.ie/html5_video/Longdesc_IDC.wmv].

Furthermore, there already exist a number of alternative mechanisms for 
providing information to users without using longdesc="", such as simply 
including the information inline, providing explicit links to long 
descriptions, and using ARIA attributes such as aria-describedby="".

Including the longdesc="" attribute in the language therefore seems like a 
poor design decision.

== Details ==

No change to the spec.

== Impact ==

=== Positive Effects ===

* Stops authors from spending time trying to use a feature that they don't 
understand and that users don't want.
* Encourages authors to include suitable information in an alternative 
form that is more likely to be accurate.
* Results in better overall accessibility on the long term.

=== Negative Effects ===

* ?

=== Conformance Classes Changes ===

No change to spec.

This would not affect existing ATs and user agents, as they can continue 
to support longdesc="" if compatibility with some set of documents where 
it is used correctly is desired. In practice, removing support is likely 
to either not be noticed (some users don't know the feature exists) or 
actually improve matters (given how poorly the feature is used in practice 
on the Web).

ARIA provides a number of alternative mechanisms that are currently not 
poisoned by existing content and that fit better into the kind of 
interaction model desired by users (according to the survey cited above). 
For example, aria-describedby="" allows an image to be related to in-page 
descriptive content.

=== Risks ===

* ?

== References ==

Links included inline.

-- 
Ian Hickson               U+1047E                )\._.,--....,'``.    fL
http://ln.hixie.ch/       U+263A                /,   _.. \   _\  ;`._ ,.
Things that are impossible just take longer.   `._.-(,_..'--(,_..'`-.;.'
Received on Sunday, 14 February 2010 08:54:39 UTC

This archive was generated by hypermail 2.3.1 : Monday, 29 September 2014 09:39:14 UTC