Biomedical Engineering Reference
In-Depth Information
Expectancy
(Subjective & objective)
based on
various information
sources
Impression
based on
the trial use
Evaluation
based on
accumulated
interactions
in the real context
Impression
based on
the memory trace
after the waste
(Consumer)
(Purchaser)
(User)
(Post-user)
Time
FIgUre 15.1
The four phases of user experience.
impression of the device and system on the basis of a trial use if they are interested in it
and motivated toward purchasing it. Usability testing as a summative evaluation is mea-
suring what corresponds to this phase. Usability testing is one type of the interactive expe-
rience, but it does not represent the total UX because the length of the test only lasts for
approximately 2 h on average and is too short to be regarded as UX.
After the purchase, people become the user and start interacting with the system in
a real context. The repetitive interactions in the real environment will be stored in the
memory of the user one by one, thus forming an evaluation of the system. Because this
part of UX as the evaluation is a cumulative experience stored in memory, its level goes up
or down depending on the quality of interaction at any time. Regarding adequate length
of the evaluation, ISO 9241-210 (2010) claims that 6-12 months is necessary, and the Users
Award Program in Sweden conducts an evaluation of information technology (IT) systems
9 months after installation.
Especially with regard to the third phase of UX, stakeholders who design the device
and system have to assess both the quality of the system architecture (accessibility) and
the quality of the system in use (usability) under the lens of user experience to evaluate
the interaction.
After wasting the device and the system, there still remains a trace of impression in the
memory. This information will serve as a basis for searching a new device or system as a
consumer in the next cyclical stage. Thus, these four phases will form a spiral structure.
The UX perspective strongly emphasizes the point that it is not possible to obtain a real-
istic evaluation by analyzing only the functionality of the system, especially in an experi-
mental setting, by using specific tools that enable evaluation of the device and system with a
certain degree of objectivity (i.e., automatic evaluation and expert evaluation). In this sense,
the UX accomplishes the User Centered Design (UCD) or the Human Centered Design
(HCD) philosophy, by shifting the focus from an old perspective of design and evaluation
focused only on the engineering aspects of the system to the new perspective that enables
the consideration of users' experience with the system in the real environment.
It is not sufficient just to consider the object (device and system) and the subject (user)
as two polarities for the interaction. The weakness of this dichotomy model is the insuf-
ficiency in taking into account the intrasystemic relation between system and user as an
emergent independent reality not reducible to components (system and user) (Federici
et al. 2005; Federici and Borsci 2010). In this sense, a member of the design team who tries
to evaluate the interaction has to be an evaluator of the intrasystemic relation between
system and user by taking into account the perspective both of the object and the subject
(see Figure 15.2).
