[CEUD-ICT] WebAIM Screen reader survey results

[Joshue O Connor]

Hi Eamon,

> But if there two different parts of the screen reader audience that  
> are diametrically opposed in their requirements -- verbose as possible  
> for beginners, brief as possible for experts -- but only one alt text  
> parameter available for each tag, 

Thats not entirely correct. The alt attribute is actually a terse
descriptor used to replace the image. It is not to provide a short
description for one user group and then a longer equivalent for the more
advanced group.

>The old longdesc chestnut is not a solution to this. 

Well, as per the HTML4 spec it is. Longdesc is a long descriptor and was
created to provide more verbose descriptions when needed. It is
unfortunately little used and poorly implemented. It is however really
useful in certain domains, education springs to mind but little used in
the wild. Longdesc is very useful in that it can be used to reference a
URI that can be on a different server, a remote URL and so on.  I always
maintained that it was really useful but just poorly implemented. It is
not in the current HTML 5 draft, it is 'retired'. A case was made for it
to be resurrected, for those interested. [1]

Also it is worth noting that both aria-labelledby and aria-describedby
properties can, and will, be used as generic descriptors to provide this
king of functionality. [2] [3]

For some explicit sample test cases using these ARIA properties see the
Codetalks wiki. [4]

> I am somewhat confused by the WebAIM survey outcome as I don't know on  
> what basis I am to choose who to serve and who to thwart when  
> formulating rules for alt text writing.

I wouldn't worry about this too much. Provide a suitable terse
description when needed using the @alt. That's it really. Whether the
user is advanced or not is neither here nor there. What is important is
providing a suitable replacement for the graphical content.

> That is, how long does it take for a beginner screen reader  
> user to get to be proficient, and how many venture on then to expert  
> level? Also, how many people are joining the beginner ranks in any  
> given year? One presumes the category populations don't stay static in  
> membership, but are they static in size?

That would be really, really useful information to have.

> I don't think the requirements of screen reader users, or any category  
> of assistive technology or technique user, should be guessed from a  
> distance by developers, designers or other web professionals. 

No. This is why user testing etc is so valuable as it provides a bridge
for developers to meet and interact with people with disabilities. It
also grounds accessibility and makes it real for them, rather than
merely a theoretical exercise.

Also note that how @alt is implemented is going to change. Gez has a
really good article on Juicy Studio that will give you a good overview
of the status of the debate. For the hardcore amongst you there is also
the verbiage of the HTML 5 ESW wiki where you can track how the issue
evolved over the last year or so. [5] [6]

Cheers

Josh

[1] http://esw.w3.org/topic/HTML/LongdescRetention
[2] http://www.w3.org/TR/2008/WD-wai-aria-practices-20080204/#DescribedBy
[3] http://www.w3.org/TR/wai-aria/#labelledby
[4]
http://wiki.codetalks.org/wiki/index.php/Set_of_ARIA_Test_Cases#describedby
[5] http://juicystudio.com/article/requiring-alt-attribute-html5.php
[6] http://esw.w3.org/topic/HTML/IssueAltAttribute




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