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Authoring and Design for the WWW
DESIGN INTO PRODUCTION
User-centred design
Designing what?
The aspects of Web sites about which design decisions can
be taken
include the...
- overall structure of linked pages
- forms of information provision
- language style and voice
- information structure within pages
- visual style
- opportunities for interaction and other feedback
In a well-designed site, all these aspects will be considered
with the user's perspective in mind.
The scope of user-centred design
The design of computer systems which are effective and
congenial for users is a huge discipline in its own right. SIGCHI, the Special
Interest Group for Computer-Human Interaction (see Web Resources, p110),
has become the largest interest group of the Association for Computing
Machinery, reflecting a shift in attitude across the whole computing industry
towards making products for people rather than expecting people to adapt their
behaviour to products.
In this handbook we can do no more than introduce some
of the key concepts of user-centred design and show how they can be applied to
design for the Web. If we have emphasised the role of the user rather than the
publisher in relation to all Web materials, this is not because the objectives and
needs of the publisher are not important, but because these objectives can
themselves best be served by aiming for a user who is stimulated and rewarded.
Constraints and the freedom to get things wrong
In the early days of the Web, only some aspects of site
design were subject to any sort of design decisions. While the overall structure
of linked pages, the language style and voice, and the information structure
within pages were all definable, many aspects of the visual style and the user's
interaction were effectively controlled by the limitations of HTML and the
decisions made in advance in the design of browser packages. This meant that,
to a certain extent, authors and publishers could apply their general knowledge
of effective communication to the new medium.
Now the Web is becoming a richer mixture of media, and
the range of possible interactions is greatly increased by developments in
browsers and the provision of component technologies through the use of plug-ins.
For those wishing to take advantage of this richness, there are obligations to
produce sites which are genuinely effective and enjoyable for users. The more
possibilities there are, the more scope there is for making an unusable,
cacophonous site. It is likely that specialist expertise in interaction design will be
needed.
Some core principles of user-centred design
User-centred design has been summarised crudely as
ensuring that 1 the user can figure out what to do, and 2 the user can tell what is
going on. These simple aims are not always as easy to achieve as they might
seem.
Weaknesses of design tend to arise in the following areas
- lack of affordances
- poor use of mappings
- inadequate feedback
Affordances are those aspects of a design which make it
self-explanatory. For example, a poorly designed photocopier will not show
where the blank paper should be inserted or how exactly it should be placed in
the machine. In a Web document, one can find hypertext triggers which look
like ordinary text or graphics, or conversely, text and graphics which are not
active, but which appear to be!
Mappings are the visible relationships between parts of a
system, or between the system and the user. Among systems with poor object-to-
object mappings, a classic example is the cooker-top which has a set of heat
rings arranged in a square but a set of controls for them arranged in a straight
line. Labels then become essential to clarify the relationship between the
controls and the objects. A Web example of poor mapping is a graphical map of
a site which shows the various pages in some particular spatial configuration,
but where this spatial model is subverted by the use of arrows pointing in
various incompatible directions within the individual pages.
Feedback is the means by which we know, for example,
that a car engine is running because we can hear it (incidental feedback) or that a
steam-boiler is in a dangerous condition because a whistle is blowing
(constructed feedback). In computer systems, almost all feedback must be
constructed by the system designers.
The provision of feedback has not hitherto been a problem
in the design of Web pages, since for simple HTML documents most of the
necessary feedback has been provided in the design of the browsers. For
example, in Netscape:
- User input is acknowledged
When the user points at a hypertext link, the
name of the linked URL is displayed in the status bar at the bottom of
the screen.
When the user clicks on a hypertext link, it
changes tone or colour instantly.
- Progress indication is provided
After a hypertext link has been activated, the
process of contacting the site and getting data from it is monitored in the
status bar.
Such feedback is taken care of by the design of the
browser, but when Web publishers incorporate other forms of interaction
in their pages, for example as Shockwave components, then it is the
responsibility of the designer to provide similar forms of feedback.
Example
If a control panel is provided as a navigation device, then
users must know:
- whether or not their action has been registered by the software, for example by use of a momentary highlight
- whether a process is taking place, for example using a progress-indicator bar
- whether the action has been successfully completed, for example by moving an indicator dot on a map of the site
Contents
Graphics Multimedia
Virtual Environments Visualisation
Contents
