topical media & game development
research directions -- establishing usability
In the March 2005 volume of CACM, an assessment is given of the
current state of
user-centered design practice.
User-centered design is, quoting
[UCD],
a multi-disciplinary
design approach based on an active involvement of users to improve the understanding of
user and task-requirements, iterative design and evaluation.
In the article, which is based on a survey among
user-centered design practitioners, user-centered design is claimed to
have been beneficial for, among others, customer satisfaction and enhanced ease of use.
Other measures mentioned are mostly relevant for e-commerce applications,
which, as the authors observe,
have greatly bolstered the the appeal of usability
and user-centered design, as users can take their business elsewhere with
just one mouse click.
In our case, the competition is fortunately less threatening.
Nevertheless, usability issues such as legibility of text, ease in navigation
and adequate task support are equally relevant.
As a first step after completing the abramovic dossier, we have developed a test-plan and
a sample task, and (the students) executed two test-sessions with participants from
ICN and Montevideo, who where asked to work with the system thinking aloud.
The test-sessions were recorded on video, and the participants
were requested to complete a questionnaire.
In [UCD], a list of approaches is given, which were reported
to have been used by the respondents of the survey:
user-centered design methods
field studies,
user requirement analysis,
iterative design,
usability evaluation,
task analysis,
focus groups,
formal/heuristic analysis,
user interviews,
prototype (without user testing),
surveys,
informal expert review,
card sorting,
participatory design
The three most frequently used methods in this list are, respectively,
iterative design, usability evaluation and task analysis.
These three methods were also considered to be important by the respondents.
Frequently used, but not considered to be as important,
were informal expert reviews.
And less frequently used, but considered important,
were field studies.
This distinction can, according to [UCD], attributed to cost-benefit trade-offs,
since clearly field studies are much more costly.
Usability evaluation looks, according to [Preece] to issues such as:
usability evaluation
- learnability -- time and effort to reach level of performance
- throughput -- the amount of work done
- flexibility -- accomodating changes in the task
- attitude -- of users to the system
To conclude this section, let's take a closer look at task analysis.
task analysis
Task analysis may be characterized as the decomposition of a task
into subtasks or steps,
to arrive at a sufficiently detailed description of the task
and its relation to the environment.
In [Euterpe], a description is given of what might be understood as
the task world ontology, the concepts and relations that play a role
in performing a task analysis.
The main concepts figuring in the task world ontology are, following [Euterpe]:
task world ontology
- task -- activity performed by an agent to reach a certain goal
- goal -- a desired state in the task world or system
- role -- a meaningful collection of tasks
- object -- refers to a physical or non-physical entity
- agent -- an entity that is considered active
- event -- a change in the state of the task world
As indicated in the diagram above,
these concepts are related in various ways.
Example relations include uses, triggers,
plays, performed_by, has, etcetera.
1
Creating a task model based on this, or a similar, ontology may help
us understand what a user needs to accomplish and how this may be supported
by an information system.
As such, creating a task model should be considered to be an
essential ingredient of the software engineering life cycle, [OO].
(C) Æliens
04/09/2009
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