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Re: [a11y-metadata-project] accessHazard

From: Charles McCathie Nevile <chaals@yandex-team.ru>
Date: Wed, 02 Oct 2013 01:48:37 +0200
To: "Madeleine Rothberg" <madeleine_rothberg@wgbh.org>, "Charles Myers" <charlesm@benetech.org>
Cc: "a11y-metadata-project@googlegroups.com" <a11y-metadata-project@googlegroups.com>, "public-vocabs@w3.org" <public-vocabs@w3.org>
Message-ID: <op.w4au3b0ay3oazb@chaals.local>
On Wed, 02 Oct 2013 00:10:42 +0200, Charles Myers <charlesm@benetech.org>  

> Charles McN had a great idea when he brought this up.  But it may  
> actually be a bit simpler to specify.
> Rather than sav
>   *   noFlashing
>   *   noMotionSimulation
>   *   noSound
> in addition to the three properties we have today
>   *   flashing
>   *   motionSimulation
>   *   sound
> we might just want to have a state of "none" (saying that you checked  
> and that there are no hazards that you are aware of).
> That would change the spec to
>   *   flashing
>   *   motionSimulation
>   *   sound
>   *   none (or noHazard)
> which makes it cleaner.  I think that saying the negative to each of the  
> three properties would be a bit tedious.  And, of course, not having the  
> property means that it has not been checked.

Yeah, but we would want to be pretty sure that "none" really means none,  
and nobody will identify a new hazard in the future that we didn't notice.  
While I suspect we are "close enough" in practice, I prefer to be really  
really conservative in this case.

I am thinking of the case where we discover that flashing at 3-7Hz is a  
problem, but certain colour changes in a given frequency that don't  
actually come across as flashing also turn out to cause problems. If we  
can figure out what they are and define them in 2023 I'd hate to have a  
million resources that say they have no hazards, when in fact we could get  
a few thousand of them properly marked with the particular hazard they do  

We need to be aware that this is messy. "Invisible metadata" will have a  
certain rate of error that can increase over time - 1/3 might not be an  
unreasonable guess although I hope it is much lower than that. As I argued  
earlier, this is still better than 80%, if we only get 20% of active  
hazards marked under the current approach. But it still implies a real  
level of risk to real people. "No risk" is a 'brave' statement, and I am  
not sure that I believe we know enough to make it reasonably accurately.

Adding the noFlashing, noSound, etc seems to me a reasonable thing to do.



> On Oct 1, 2013, at 1:38 PM, Madeleine Rothberg  
> <madeleine_rothberg@wgbh.org<mailto:madeleine_rothberg@wgbh.org>>
>  wrote:
> Chuck has updated the issues list to include the discussion of whether
> accessHazard should state positive or negative information. See that post
> and my comments, which are also below, at:
> [http://www.w3.org/wiki/WebSchemas/Accessibility/Issues_Tracker#accessHazar
> d_-_Ok_as_is.2C_or_should_it_be_negated_in_sense.3F]
> I believe we need both accessHazard=flashing and accessHazard=noFlashing,
> etc.. This is because there are three cases we'd like to distinguish:
> 1. checked and it's fine
> 2. checked and it is NOT fine
> 3. didn't check
> "Didn't check" can be signified by no metadata -- this will be most of  
> the
> content on the Web. In cases where someone has checked, let's record both
> positive and negative states.
> -Madeleine
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Charles McCathie Nevile - Consultant (web standards) CTO Office, Yandex
       chaals@yandex-team.ru         Find more at http://yandex.com
Received on Tuesday, 1 October 2013 23:49:09 UTC

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