W3C home > Mailing lists > Public > public-comments-wcag20@w3.org > May 2007

Your comments on WCAG 2.0 Last Call Draft of April 2006 (1 of 3)

From: Loretta Guarino Reid <lorettaguarino@google.com>
Date: Thu, 17 May 2007 16:36:01 -0700
Message-ID: <824e742c0705171636o62a8f7d4p58610aa798f0516d@mail.gmail.com>
To: "Jason White" <jasonw@ariel.its.unimelb.edu.au>
Cc: public-comments-WCAG20@w3.org

Dear Jason White ,

Thank you for your comments on the 2006 Last Call Working Draft of the
Web Content Accessibility Guidelines 2.0 (WCAG 2.0
http://www.w3.org/TR/2006/WD-WCAG20-20060427/). We appreciate the
interest that you have taken in these guidelines.

We apologize for the delay in getting back to you. We received many
constructive comments, and sometimes addressing one issue would cause
us to revise wording covered by an earlier issue. We therefore waited
until all comments had been addressed before responding to commenters.

This message contains the comments you submitted and the resolutions
to your comments. Each comment includes a link to the archived copy of
your original comment on
http://lists.w3.org/Archives/Public/public-comments-wcag20/, and may
also include links to the relevant changes in the updated WCAG 2.0
Public Working Draft at http://www.w3.org/TR/2007/WD-WCAG20-20070517/.

PLEASE REVIEW the decisions  for the following comments and reply to
us by 7 June at public-comments-WCAG20@w3.org to say whether you are
satisfied with the decision taken. Note that this list is publicly

We also welcome your comments on the rest of the updated WCAG 2.0
Public Working Draft by 29 June 2007. We have revised the guidelines
and the accompanying documents substantially. A detailed summary of
issues, revisions, and rationales for changes is at
http://www.w3.org/WAI/GL/2007/05/change-summary.html . Please see
http://www.w3.org/WAI/ for more information about the current review.

Thank you,

Loretta Guarino Reid, WCAG WG Co-Chair
Gregg Vanderheiden, WCAG WG Co-Chair
Michael Cooper, WCAG WG Staff Contact

On behalf of the WCAG Working Group

Comment 1:

Source: http://www.w3.org/mid/20051127002653.GA4244@jdc
(Issue ID: LC-492)

Part of Item:
Comment Type: ED
Comment (Including rationale for any proposed change):

Whereas guideline 2.2 is framed in terms of "time limits" on reading
and interaction. criterion 2.2.1 instead uses the term "time-out".
Neither "time limit" nor "time-out" is defined. This difference in
terminology raises the question of whether there is meant to be a
distinction between the two concepts. I don't think there is, or ought
to be, such a distinction.

Proposed Change:

Use the term "time limits" in 2.2.1, in the same sense as in the text
of guideline 2.2 itself. More generally, use "time limit" wherever
"time-out" appears in WCAG 2.0. If appropriate, add a glossary entry
to clarify the meaning of the term - I think the text of guideline 2.2
is a clear and precise formulation of what is meant.

Response from Working Group:

Time-out is a specific type of time limit. Time-out is the correct
term for SC 2.2.1. Time-out is a commonly understood term on the Web
and we are not using it in a special way, so we don't think it needs a

Comment 2:

Source: http://www.w3.org/mid/20060501072115.C8C0DBDA7@w3c4.w3.org
(Issue ID: LC-481)

Part of Item:
Comment Type: ED
Comment (Including rationale for any proposed change):

In the definition of "Web unit":
"identified by a single Uniform Resource Identifier (such as URLs)"

This is not only grammatically wrong but rather sloppy language for a

Proposed Change:

"identified by a single Uniform Resource Identifier (URI)"

Consider whether to add a note stating that a URI is either a Uniform
Resource Locator (URL) or a Uniform Resource Name (URN). Is this still

Response from Working Group:

We changed  "identified by a single Uniform Resource Identifier (such
as URLs)" to "identified by a single Uniform Resource Identifier

Comment 3:

Source: http://www.w3.org/mid/20060516092236.8BE26BDA8@w3c4.w3.org
(Issue ID: LC-482)

Item Number: Conformance claims
Part of Item:
Comment Type: TE
Comment (Including rationale for any proposed change):

The main principle which distinguished level 1 from level 2 success
criteria in the November 2005 working draft, namely that level 1
criteria may not, whereas level 2 criteria may impose constraints on
expression and presentation of material, has been abandoned in the
Last Call draft. No substitute principle has taken its place. All that
the conformance section now states is that level 1 criteria constitute
the minimum, and level 2 requirements offer an enhanced level of
accessibility. Level 3 is distinguished in so far as these criteria
may not be applicable to all Web content.

The lack of a principled distinction between level 1 and level 2 is a
significant weakness of the guidelines as currently drafted, for
several reasons. First, it invites fragmentation of the standard by
failing to offer any defensible ground for the allocation of success
criteria to conformance levels. In contrast, confidence in the
integrity of the WCAG 1.0 conformance scheme, in so far as it worked,
is bulstered by the fact that there was a coherent underlying
rationale determining the assignment of priorities to checkpoints; one
was not asked simply to trust the judgment of the working group in
this respect.

Secondly, the WCAG 2.0 levels impose de facto priorities upon success
criteria. The difference between WCAG 1.0 "priorities" and WCAG 2.0
"levels" is in name only. Level A conformance, as in WCAG 1.0, still
requires satisfaction of all level 1 items, and correspondingly at
level 2 and even at level 3, where a 50% minimum is arbitrarily
imposed. Developers must, therefore, despite statements in the
guidelines to the contrary, treat level 1 items as more important than
level 2 items, and level 2 items as more important than those at level
3. Yet, unlike WCAG 1.0, there is no rationale, based on impact or any
other concept, that determines and justifies these distinctions among
priorities (now called "levels"). Implementors, policy makers and
other audiences have no reason to believe that the allocation of
levels to success criteria is anything better than the outcome of

This shortcoming of the guidelines needs to be remedied in two steps.
First, the working group should agree upon one or more clear,
pertinent and applicable criteria to distinguish level 1 from level 2
items. Secondly, the whole document should be reviewed in light of
these criteria, re-allocating success criteria to levels as needed to
bring the guidelines into accord with the chosen principles.

Alternative proposals are provided below. These are not intended to be
exhaustive of the possibilities; other solutions may, and should, also
be considered.

Proposed Change:

Option 1. Reinstate the principle that level 1 success criteria enable
user agents and other tools to adapt the content to meet a wide range
of access requirements, without imposing constraints on the expression
or presentation of the content. Level 2 criteria make the content
directly accessible by regulating expression and presentation as
needed to achieve a high degree of accessibility.

Option 2: Establish "impact", as in WCAG 1.0, as the main distinction
between level 1 and level 2 criteria, while acknowledging that this
does not apply to requirements primarily aimed at aiding cognition.
For success criteria primarily related to cognitive disabilities,
establish a requirement that level 1 criteria do not impose
constraints on the expression, whether linguistically, graphically,
auditorily etc., of the content. This leads to the following:

a. At level 1, success criteria eliminate barriers that would
otherwise make it impossible, due to a sensory or physical disability,
to access the content. At level 2, success criteria overcome barriers
that would otherwise make it very difficult, due to a sensory or
physical disability, to access the content. Level 3 criteria further
facilitate access (as in WCAG 1.0 priority 3).

b. Level 1 criteria substantially enhance the effectiveness with which
people with cognitive disabilities can access the content, without
imposing constraints on the expression, whether in language, sound or
images, of the information and functionality provided by the content.
Level 2 criteria further facilitate cognition by requiring content to
be expressed in ways that improve its accessibility to people with a
variety of cognitive disabilities. Level 3 criteria are the same as
level 2, but place requirements on expression that cannot be applied
to all types of content.

Option 3: Establish a metric of implementation difficulty that is
applicable across technologies and will remain stable over time. This
would roughly correspond to the amount of effort required of an author
to implement the success criteria. Level 1 criteria would demand
minimal effort while substantially overcoming barriers to access,
level 2 more effort, and level 3 still further. The measure of
"difficulty", "effort" or whatever, would provide the basis for making
this distinction more precise. I doubt whether such an idea can be
worked out in practice, and I along with other proponents of enhanced
accessibility would object to its introduction into the guidelines

- benefit to people with disabilities, rather than impact on authors,
should be the primary means of distinguishing among conformance
levels. Also, such an approach would promote the idea that
accessibility is a burden rather than an opportunity, clearly an
undesirable result.

Option 4: Divide the success criteria in WCAG 2.0 into two categories:
(a) "general": criteria applicable to all types of Web content; and
(b) "special": criteria only applicable to some types of Web content.
This distinction is already used, albeit roughly, to separate out
certain of the criteria currently classified as at level 3. Under this
proposal, define the three conformance levels as follows:

  Level A conformance means that half (50%) of the general success
criteria are satisfied.

  Level AA conformance means that all of the general success criteria
are satisfied.

  Level AAA conformance means that all of the general success
criteria, and all of the special success criteria applicable to the
type of content involved, are satisfied.

  The "special" success criteria would have to be defined and grouped
into categories to make clear which should be applied to which kinds
of content, and how the different types of content could be
distinguished. Note also that additional aids to cognition -
controlled vocabularies, symbol systems, etc., could be itnroduced as
"special" criteria in the sense indicated in this proposal. They could
also be introduced at level 3 under other proposals outlined above.

Variations on the above proposals can of course easily be created.

Whatever proposal is chosen, whether one of the above or not, the
success criteria must all be reviewed and, as necessary, reclassified
in accordance with it.

Response from Working Group:

The description of conformance levels in WCAG 2 has been rewritten to
clarify these issues:

The word "levels" does not mean that some success criteria are more
important than others. Each success criterion in WCAG 2.0 is essential
to some users, and the levels build upon each other. However, even
content that conforms at AAA (triple-A) may not be fully accessible to
every person with a disability.

*In general, Level A success criteria achieve accessibility by
supporting assistive technology while putting the fewest possible
limits on presentation. Thus people with a wide range of disabilities
using a wide range of assistive technologies, from voice input and
eye-tracking devices to screen readers and screen magnifiers, are able
to access content in different ways. In other words, Level A success
criteria support the ability of both mainstream and specialized user
agents to adapt content to formats that meet their users' needs.

*The success criteria in Level AA provide additional support for
assistive technology. At the same time, they also support direct
access to content by the many people who use conventional user agents
without assistive technology. In general, Level AA success criteria
place more limits on visual presentation and other aspects of content
than the success criteria in Level A.

*Level AAA success criteria increase both direct access and access
through assistive technology. They place tighter limits on both
presentation and content.

Comment 4:

Source: http://www.w3.org/mid/20060501070437.1B6DFBDA7@w3c4.w3.org
(Issue ID: LC-464)

Item Number: Related Documents
Part of Item:
Comment Type: TE
Comment (Including rationale for any proposed change):

Conformance: Aggregated Content.

If content contains authored units that do not themselves carry any
conformance claims, and those authored units are modified or
substituted as a result of an aggregation process, then the
conformance status of those authored units is unknown at any point in
time unless individual assessments are carried out. Such assessments
may be impractical, for example on sites that collect comments from
the public, maintain e-mail archives, etc.

As the guidelines are currently drafted, the conformance of any Web
unit containing such authored units depends in turn on the conformance
of those authored units, which may vary over time. In order to avoid
making false conformance claims, the operator of such a Web site
would, presumably, have to exclude such Web units from the scope of
any conformance claim, in accordance with the scoping provisions of
the conformance section. I think this consequence needs to be
clarified and stated explicitly.

Alternatively, the scoping provisions could be modified to allow
individual authored units to be excluded from the ambit of a claim,
but in that case it is by no means clear how the "authored units"
could be precisely identified and specified in the claim.

Proposed Change:

Clarify that if it is unknown whether an authored unit participating
in aggregation conforms to WCAG 2.0, or which level of conformance is
achieved, then it is likewise unknown what, if any, level of
conformance is attained by Web units in which it appears. Implementors
should be advised to exclude Web units containing such "unknown"
authored units from the scope of any conformance claim in accordance
with the "scoping" provisions of the conformance section of WCAG 2.0.

Note that by controlling what may appear in authored units
participating in  the aggregation process, through technical or other
means, it may be possible to ensure that a given level of conformance
is always satisfied. Under these circumstances (where the conformance
of resulting Web units is guaranteed), conformance claims with respect
to such aggregated content may reliably be made.

Response from Working Group:

We have made conformance claims less regulatory and more descriptive,
that is, a conformance claim describes what is conformant to the
guidelines.  We think it is more appropriate for policy makers to
determine appropriate exceptions.

We have provided a way to make a statement about parts of a page that
do conform if the whole page doesn't.

We have clarified the situation by removing all exceptions and adding
the following at the end of the conformance section:

Note:  If pages can not conform (for example, conformance test pages
or example pages) they would not be included in the conformance claim.

Statement of partial conformance

Sometimes, Web pages are created that will later have additional
content added to them. For example, an email program, a blog, or an
article that allows users to add comments to the bottom. Another
example would be a company or individual who compiles a page from
multiple sources. Sometimes, the content from the other sources is
automatically inserted into the page over time.

In both of these cases, it is not possible to know at the time of
original posting what the content of the pages will be. Two options
are available:

   1. A conformance claim is made based on best knowledge. If a page
of this type is monitored and kept conformant (non-conforming content
is immediately removed or made conforming) then a conformance claim
can be made since, except for error periods, the page is conformant.
No conformance claim should be made if it is not possible to monitor
or correct non-conforming content.
   2. A "statement of partial conformance" is made. A statement that
the page does not conform, but could conform if certain parts were
removed can be made. The form of that statement would be, "This page
would conform to WCAG 2.0 at level X if the following parts from
uncontrolled sources were removed."
         1. This "statement of partial conformance" cannot be used for
content that is under the author's control.
         2. The "following parts" of the page that would need to be
removed would be described in terms that users can understand. (e.g.
they can't be described as "all parts that we do not have control of"
unless they are clearly marked as such.)

Comment 5:

Source: http://www.w3.org/mid/20060516092236.8BE26BDA8@w3c4.w3.org
(Issue ID: LC-483)

Part of Item:
Comment Type: TE
Comment (Including rationale for any proposed change):

The conformance section is not sufficiently precise in stating what
must be included in a baseline. Specifically, a baseline must specify
a list of technologies, including minimum versions, where applicable,
thereof, that are required to be supported in order for the content to
be rendered to, and operated by, the user.

Proposed Change:

In the "required components of a conformance claim" section, explain
clearly that, where applicable (i.e., where there exist multiple
versions of a technology), the minimum version required to be
supported and enabled in user agents must be stated as part of the
baseline. More explicitly, the baseline must name each technology
together with the minimum required version, where applicable.

Response from Working Group:

The following sentence was added to the end of the section titled
"Rules for Supported Technologies":

"When citing technologies as supported, the version(s) must be specified."

Comment 6:

Source: http://www.w3.org/mid/20060501071533.46EEABDA7@w3c4.w3.org
(Issue ID: LC-484)

Part of Item:
Comment Type: ED
Comment (Including rationale for any proposed change):

"If individual authored units do not carry a conformance claim, then
the claim must be based on the Web unit with the authored units in
place." This is expressed in terms of claims rather than in terms of
conformance. It should be more accurately stated thus:

"If individual authored units do not carry conformance claims, then
the conformance of any Web units in which they occur is determined as
the level of conformance, if any, attained by those Web units with all
aggregated content in place".

Proposed Change:

See wording proposed above.

Response from Working Group:

We have completely revised the conformance section. Issues related to
aggregation are now discussed in the section "Statement of partial
conformance" at
http://www.w3.org/TR/2007/WD-WCAG20-20070517/#conformance-partial .

Comment 7:

Source: http://www.w3.org/mid/20060503105009.8E353BDA7@w3c4.w3.org
(Issue ID: LC-485)

Part of Item:
Comment Type: TE
Comment (Including rationale for any proposed change):

Sc 1.1.1: "If non-text content is pure decoration, or used only for
visual formatting, or if it is not presented to users, is the above
meant to apply to auditory content, e.g., sound efects or background
sounds used only for aesthetic purposes and which is incidental to the
meaning and functionality of the Web unit? In other words, can a sound
be "pure decoration", or is the provision restricted to visual
material? My own view is that it should apply irrespective of the
modality of the "decoration", namely to auditory content as well as

Proposed Change:

Perhaps add a parenthetical such as "pure decoration (whether auditory
or visual)".

Response from Working Group:

The 1.1.1 success criteria on decorative non-text content does not
specify that it applies only to visual content.  On the other hand the
working group was unable to identify ways to mark audio so that AT
could ignore it.  Did you have something in mind?

Comment 8:

Source: http://www.w3.org/mid/20060504145505.6105547BA1@mojo.w3.org
(Issue ID: LC-487)

Part of Item:
Comment Type: TE
Comment (Including rationale for any proposed change):

Guideline 1.2 does not require, at any conformance level, audio
descriptions of live video; only prerecorded video is covered. Audio
description of live video is possible, at least in some circumstances.
It can indeed be accomplished at a high level of quality, as in live
plays where describers have access to scripts in advance. In other
situations, such a degree of quality and accuracy may not be
attainable, but descriptions could still be attempted. Are there
situations in which it would be technically and practically infeasible
to provide audio descriptions of live video? If so, this item could be
introduced at level 3, otherwise it is a candidate for level 2.

Proposed Change:

Add a success criterion at an appropriate level requiring audio
descriptions of live video.

Response from Working Group:

A criterion similar to this proposal was included in previous drafts
of WCAG 2.0. However, the working group decided to remove it since
this is almost impossible to do unless the live multimedia is
scripted. The working group did not feel that live scripted events
were applicable to a wide enough range of web content to be included
at the success criterion level, but has included an advisory technique
(details to be completed in a future draft) about providing audio
descriptions for live multimedia.

Comment 9:

Source: http://www.w3.org/mid/20060505011902.214C1BDA7@w3c4.w3.org
(Issue ID: LC-488)

Part of Item:
Comment Type: ED
Comment (Including rationale for any proposed change):

Sc 1.3.1 refers to "information and relationships", whereas guideline
1.3 is expressed in terms of "information and structure". If there is
supposed to be a subtle difference between these terms, it needs to be
defined and explained. Otherwise, the same wording should be used in
both the guideline and the success criterion. I don't think there is,
or ought to be, any difference in meaning.

Proposed Change:

Change sc 1.3.1 to read "information and structure".

Response from Working Group:

Guideline 1.3 has been reworded to avoid this confusion. The new
wording is "Create content that can be presented in different ways
(for example spoken aloud, simpler layout, etc.) without losing
information or structure."
Received on Thursday, 17 May 2007 23:36:20 UTC

This archive was generated by hypermail 2.4.0 : Friday, 17 January 2020 19:14:43 UTC