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SC 2.4.3 source order

From: Web Usability <rhudson@usability.com.au>
Date: Tue, 20 Dec 2005 17:07:06 +1100
To: "Public-Comments-Wcag20" <public-comments-wcag20@w3.org>
Message-ID: <GGEEINFOLDEIIBPBECEMGEBOCGAA.rhudson@usability.com.au>

Hi WCAG Working Group

Comments on WCAG 2.0, Success Criterion 2.4.3 follow:

SC 2.4.3 states:

"2.4.3 Blocks of content that are repeated on multiple perceivable units are
implemented so that they can be bypassed. (Level 2)"

The "Understanding WCAG 2.0 (Working Draft 23 November 2005)" document,
provides the following advice in relation to meeting this criterion.

Start quote:
Techniques for Addressing Success Criterion 2.4.3
The following combinations of techniques are deemed to be sufficient by the
WCAG Working Group for meeting success criterion 2.4.3.
 Using a technology-specific technique to group blocks of repeated material
in a way that they can be skipped.
 Using a technology-specific technique to create links to skip blocks, and
using one of the following techniques to skip blocks of repeated material
Note: (Note: It is preferred that these links be visible.)
	o  Adding a link at the top of each page that goes directly to the main
content area.
	o  Adding a link at the beginning of a block of repeated content to go to
the end of the block.
	o  Adding links at the top of the page to each area of the content.
	o  Structuring the content so the main content comes first (in structure -
but the default presentation may be a different order), and adding links to
the blocks of repeated content."
End quote.

I am concerned with the requirement to structure the content so the main
content comes first. While at first glance this might seem like a good idea
that will benefit screen reader users, I would be very interested to learn
about the research that was used to underpin this requirement.

I was recently involved in a research project that looked in part at this
question. We observed four screen reader users and surveyed a further eight
in order to see if they preferred the main content of the page to be
presented first (in the source order). The twelve participants were all
required to use two sites for specific tasks. The sites were very similar
apart from the relative order of the site navigation elements and the main
content of each page.

Following our research, we feel that the order in which a screen reader
presents the material on a web page is likely to be of little importance to
all, but the most inexperienced screen reader users. And, for the
inexperienced screen reader user, presenting the informational content
before the navigation is more likely to be a source of confusion rather than
a benefit.

We concluded that in our view, at this stage CSS should not be used to
present the informational content of a page in the source order before the
page navigation schema. However, it is probably desirable to present the
informational content before extraneous information, such as advertisements
and related links, as well as the page footer.

Our research also looked at the difficulty screen reader users have in
identifying different navigational components of a web page. When most web
pages are displayed graphically, it is usually easy for a sighted person to
clearly identify the different navigation menus, for example main navigation
across the top and second level navigation down the side. However, when
doing accessibility evaluations in the past I have often noticed that screen
reader users can have difficulty identifying and differentiating the various
navigation menus that are on a page.

Some of the test sites we prepared for this research project contained
structural labels identifying the different levels of navigation on the
page. Although it is likely many of the site testers and final survey
respondents were not used to the different levels of navigation being
labelled, all said they found inclusion of these structural labels on the
test sites very useful.

In our opinion, structural labels should be used since they seem to
effectively address a significant problem some screen reader users have in
identifying the different navigation elements on a page. Also, through the
use of CSS it is possible to include these labels without affecting the
visual appearance of the page.

We presented our findings at the OZeWAI 2005 Conference in Melbourne. The
slides used for the presentation can be found at

A written report describing the research process and our findings will be
posted on the same site in the near future.
Received on Tuesday, 20 December 2005 06:07:33 UTC

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