Information Technology Reference
In-Depth Information
some reasons to pursue a usability evaluation are to: (a) obtain feedback
and guidance for improving design and development; (b) measure whether
user and/or organizational objectives (e.g., requirements and usability
goals) have been achieved; and (c) investigate long term use in a realistic
usage environment [13]. In the article “User studies: Why, how, and
when”
[14] the authors present these reasons for evaluation in
visualization when assessing the strengths and weaknesses of a technique:
x
investigate why and for what (task users, data etc.) a particular
technique gives good performance,
x
demonstrate that a novel technique is useful to intended users
according to some objective criteria (usability goal expressed in
terms of, for example, effectiveness, efficiency, satisfaction),
x
demonstrate that a novel technique is more appropriate than an
existing one,
x
investigate whether theoretical principles from other disciplines
transfer to an information visualization context of use,
x
provide predictions of good use and usability.
The authors also provide useful examples of how and when to conduct
studies and how to make use of the results [14].
Conducting and evaluating a study, and accomplishing the purposes
described depend on several important issues:
x
the phase of development and the state of the visualization,
x
the level of control the researcher can apply to the study,
x
the researcher's expertise, or possibilities to collaborate with
colleagues more experienced in evaluation methodology and
data analysis,
x
resources available in terms of participants, time, equipment
etc.
Finally, and importantly, the choice of methodology and procedure to
apply in an evaluation study must always stem from, and be appropriate to,
the actual problem or research question that is related to the information
visualization technique subject to the study.
A variety of classifications of evaluation methods exist (see, for
example, [11] and [15]). Bowman, Gabbard, and Hix [16] present a
classification of usability evaluation methods for virtual reality also
relevant to information visualization. The authors compare methods
according to three characteristics: (1) whether representative users
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