Re: Issues: Part 3 - #44 and #45 - Follow-up

Issues #44 and #45 - Follow-up

This memo follows up on Issues #44 and #45 in my 18 November 1999 memo 
(http://lists.w3.org/Archives/Public/w3c-wai-ua/1999OctDec/0349.html).

Thanks to David Poehlman, Ian Jacobs, Jon Gunderson, and Bryan Campbell for 
feedback and comments.

There is an issue about how the UAAG requirements ought to apply to 
assistive technologies. I suggest four steps to resolve this problem.

1. Add to the definition of "Applicable checkpoint" a bullet item that make 
inapplicable checkpoints that require technology that does not yet exist. 
2. Make an explicit exemption for user agents that are designed and 
developed exclusively for individuals with disabilities.
3. Refine the Abstract.
4. Consider the possibility of adding another Conformance category called 
"Exempt". I have not added that and I am not sure that it is necessary.

Please note that this memo includes some edits/revisions that are unrelated 
to this issue, so please consider them even if my solution to this issue is 
not accepted. 

Note that in the revised definition I have delimited the changed sections 
with the <CHANGE> and </CHANGE> tags.

SOLUTION

1. Revised  version of "Applicable checkpoint".

This revision contains a couple one or two small additional edits beyond 
what was in yesterday's memo.

New:
{Note the following highlights changes from the 5 November UAAG document.}
Applicable checkpoint
If a user agent offers a functionality, it must ensure that <CHANGE> people 
with disabilities </CHANGE>  have access to that functionality or an 
equivalent alternative. Thus, if the user agent supports keyboard input, it 
must support accessible keyboard input. If the user agent supports images, 
it must ensure access to each image or an alternative equivalent supplied 
by the author. If a user agent supports style sheets, it must implement the 
accessibility features of the style sheet language. If the user agent 
supports frames, it must ensure access to frame alternatives supplied by 
the author.
Not all user agents support every content type, markup language feature, 
input or output device interface, etc. When a content type, feature, or 
device interface is not supported, checkpoints with requirements related to 
it do not apply to the user agent. Thus, if a user agent supports style 
sheets at all, all checkpoints related to style sheet accessibility apply. 
If a user agent does not support style sheets at all, the checkpoints do 
not apply.
The applicability of checkpoints related to markup language features is 
<CHANGE> determined </CHANGE> similarly. If a user agent supports tables, 
it must support the accessibility features of the language related to 
tables (or images, or frames, or video, or links, etc.). The Techniques 
Document includes information about the accessibility features of W3C 
languages such as HTML, CSS, and SMIL.
The following summarizes criteria for applicability. A checkpoint applies 
to a user agent unless: {NOTE NEW ORDER OF THE BULLET ITEMS}
(bullet 1) The checkpoint refers <CHANGE> solely </CHANGE> {not sure if 
this is essential, may be OK as is} to an unsupported input or output 
device interface. Note that if the interface is supported at all, it must 
be supported accessibly.
(bullet 2) The checkpoint definition states explicitly that it only applies 
to a different class of user agent.
[Old - Deleted: (bullet) "The checkpoint includes requirements about a 
content type (script, image, video, sound, applets, etc.) that the user 
agent does not recognize at all."]
(bullet 3) {NEW}: "The checkpoint includes requirements about a content 
type (script, image, video, sound, applets, etc.) that the user agent 
<CHANGE> either does not recognize or </CHANGE> recognizes but does not 
support natively." {This is a combination of bullet points.}
(bullet 4) The checkpoint <CHANGE> requires control of </CHANGE> {Old: 
"refers to the"} properties of an embedded object (e.g., video or animation 
rate) that may not be controlled or accessed by the user agent.
<CHANGE> (bullet 5) The checkpoint <CHANGE> requires technologies that are 
unsupported by the user agent (e.g., markup language, synchronized 
multimedia, metadata description language, etc.).</CHANGE>  {IMPORTANT 
NOTE. I changed this to indicated by whom or what it is unsupported. Please 
correct me if this was not the intent. Old (5 Nov 99): "The checkpoint 
includes requirements about an unsupported markup language or other 
technology (e.g., style sheets, mathematical markup language, synchronized 
multimedia, metadata description language, etc.)".}
<CHANGE> (bullet 6) The checkpoint requires technology that does not yet 
exist.</CHANGE>  {This provision might protect makes of telephone-based Web 
browsers. There is not yet any good way to interface the device to braille 
output or visual display. The idea is that a checkpoint is not applicable 
if technology does not exist that would allow the user agent to interact 
accessibly with other user agents. }

<CHANGE> {New Paragraph}User agents that are designed and developed 
exclusively for people with disabilities are exempt from the requirements 
of this document.{Note. I really think that we need some serious input from 
developers of assistive technologies on this issue.}
</CHANGE> 
{end of New}
----
2. Revised Section on Applicability.

<CHANGE> {Note. This section has several changes from yesterday's version 
so I am marking the whole thing as changed.}
1.6 Applicability. User agents must satisfy all the _applicable 
checkpoints_ for a chosen conformance level. Not every checkpoint or 
guideline is applicable to every user agent. Generally, a user agent must 
adhere to checkpoints that ensure accessibility of functionalities that it 
offers to users, but is generally not required to address checkpoints that 
address the accessibility of functionalities that it does not provide. This 
means that for user agents such as graphical Web browsers which are 
general-purpose user agents for accessing the virtually all Web content, a 
greater portion of the checkpoints will be applicable. On the other hand, 
applications or utilities with a much narrower range of functionality will 
tend to have a smaller set of applicable checkpoints. See the definition of 
"Applicable checkpoint" in the appendix ("Terms and Definitions") for 
greater detail."{Note. If necessary, this section could bring in more 
material from "Terms and Definitions -- Applicable checkpoint" if 
necessary.}

User agents that are designed and developed exclusively for people with 
disabilities are exempt from the requirements of this document. These user 
agents are ordinarily classified as "assistive" technologies or devices, 
though not all assistive technologies are necessarily eligible for this 
exemption. Note that this exemption is for individual user agent products, 
not for minor adaptations of user agents designed for more general 
audiences. Notwithstanding this exemption, developers of all user agents 
are encouraged to adhere as closely possible to the guidelines in this 
document. {Note. I think that this exemption is important because it 
protects developers who are working with innovative, experimental, small 
market products for people with disabilities.}
</CHANGE> 

{Note. I have not indicated anything about whether the developer of an 
assistive technology could waive their exemption. One can spend forever 
trying to anticipate all the exceptions. Again, I would be very interested 
in feedback from developers of assistive technologies to see if they feel 
that they need the exemption}

3. Revised Abstract

Old (5 Nov 99):

"Abstract:"

"This document provides guidelines to user agent developers for making 
their products -- browsers, multimedia players, plugins -- accessible to 
people with disabilities. An accessible user agent allows users with 
disabilities to retrieve and view Web content or to enable access when used 
in conjunction with other software or hardware, called assistive 
technologies. These guidelines discuss the accessibility of the user agent 
as well as how the user agent communicates with assistive technologies such 
as screen readers, screen magnifiers, braille displays, and voice input 
software."

My current (19 November 1999) suggestion:

New:

"Abstract:"

<CHANGE> "This document provides guidelines to user agent developers for 
making their products -- browsers, multimedia players, plug-ins, and other 
technologies used to access Web content -- accessible to people with 
disabilities. Developers must ensure: (1) that the functionalities offered 
by the user agent are accessible, and (2) that the user agent works well 
with other user agents that provide additional functionalities that are 
necessary for full access to Web content. For example, the developer of a 
graphical desktop Web browser will ensure that its functionalities are 
accessible to individuals who have difficulty using a pointing device (e.g.,
 mouse), such as many individuals have visual disabilities. The developer 
will also use standard ways of interfacing the browser with other user 
agents, such as movie and audio players, and assistive technologies such as 
screen readers, screen magnifiers, braille displays, and voice input 
software. Not every guideline or checkpoint is applicable to every kind of 
user agent. User agents that are accessible can be more flexible, powerful, 
and usable for all users."
</CHANGE>

{With regard to the issue of assistive technology, this revised abstract 
mentions it fewer times, since some assistive technologies will be 
exempted. Of course, they are still user agents and other user agents 
should be developed to work well with them.}

=============================
Eric G. Hansen, Ph.D.
Development Scientist
Educational Testing Service
ETS 12-R
Rosedale Road
Princeton, NJ 08541
(W) 609-734-5615
(Fax) 609-734-1090
E-mail: ehansen@ets.org

Received on Friday, 19 November 1999 17:26:21 UTC