Evaluation results: Navigation

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Participants were observed to perform two types of 'finding' task while
using the Guidelines: finding a topic initially; and re-finding a section
after reading it or seeing a reference to it.  They had difficulties with
both of these tasks, for several different reasons.

Problem with initial finding:
The Table of Contents does not currently support authors in finding
guidelines for particular topics, such as images, frames, forms (although
it is an improvement on previous versions).

Potential solution:
* Perhaps in addition to the existing list of guidelines in the Table of
Contents, a list of HTML topics could also be provided.

Problem with re-finding:
Several factors seemed to contribute to the difficulties with re-finding
sections or references to sections, including the ability to keep track of
which document was being viewed.
When Participants followed a link from the Guidelines to the Techniques
they did not seem to be aware that they had moved into a different
document; the transition was almost too seamless.  Participants were
observed to follow a link to the Techniques and then scroll up to try to
return to the link they had followed, as if they were still viewing the
same document.

Potential solutions:
* Link text could be modified to include information about which document
the destination of a link is in. (See below for more on link text.)

* Could the final URL be made shorter and less complex?  A participant
pointed out that the URL was interfering with their usual strategy for
keeping track of where they were: it was too long to fit in the status bar
of their browser which meant they could not check the destinations of
links.  They also said that it was too complex to easily spot when it
changed when they moved between documents.

* Could the section numbers indicate the current document, such as G1.1 or
T2.2?  Is there a way in which the numbering could match across the
documents, for example, could G1.1 relate to T1.1?

There may be other solutions to this which are visual in nature, such as
colour-coding, but non-visual solutions are more difficult to identify.

Related problem: Link text.
Participants often found that links did not take them where they expected,
for example:
- In Guideline 2 it is not clear where the link "important" goes to.
- In Guideline 2 the link "long description" goes to information on long
descriptions, whereas the link "a long description" in Checkpoint 2.1 goes
to examples.
- In Checkpoint 1.3 the link "provide a text equivalent" goes to examples
for imagemaps, whereas the link "provide a text equivalent" in Checkpoint
2.2 goes to examples for images.

Don't the Guidelines (or the Techniques) state somewhere that links with
the same text should go to the same destination?

Potential solution:
* If a link is to a definition, or examples, or further description this
could be indicated, for example, <link> definition of important, <link>
examples of long descriptions for imagemaps, <link> further information on
long descriptions, etc.

* It may also help if the document is indicated as well as the content at
the destination, such as <link> Techniques for providing text alternatives
for images.  This link text is rather long, but it clearly indicates the
destination of the link.

Related problem: position of links.
In Checkpoint 1.1 the link "Provide text equivalents for all images" goes
to Techniques Checkpoint 1.1 (examples) where the first few words are a
link with same text, "Provide text equivalents for all images", back to
Checkpoint 1.1 in the Guidelines.  In both locations the first words an
author would read are a link to somewhere else.  This is the case for many

Potential solution:
* The link text could indicate that it links to some examples, and could
also be moved from the beginning of the Checkpoint to the end, for example:

1.1 <no link> Provide text equivalents for all images [Priority 1]
For example, in HTML, use the "alt" attribute of the IMG and INPUT
elements, or for OBJECT, use "title" or the element's content. <link>
Examples of providing text equivalents.

This could be applied to many of the Checkpoints.

Finally, Checkpoint 15.5 recommends the use of a site map. A participant
suggested that the Guidelines could use one because it can be difficult to
navigate between the documents.


Chetz and Helen.

Chetz Colwell and Helen Petrie,
<c.g.colwell@herts.ac.uk>, <h.l.petrie@herts.ac.uk>.
Sensory Disabilities Research Unit,
University of Hertfordshire,
Tel: +44 1707 284629
Fax: +44 1707 285059

Received on Saturday, 13 March 1999 07:39:21 UTC