Biomedical Engineering Reference
In-Depth Information
agreement of the international scientific community. Moreover, this new unit of measure-
ment should also respect the principles of economy (i.e., efficiency and efficacy), meaning
that it should be able to lessen the costs for the identification of problems in an interaction
evaluation.
In this sense, the interaction problems are considered as the units of the distance between
the two mental models (Figure 15.4). The evaluator's mental model, just like the other two,
Designer's mental model
User's mental model
Problem solving
representation of
knowledge expertise etc...
Problem solving
representation of knowledge
expertise (navigation skills)
etc...
Conceptual model
Real user
Hypothetical intrasystemic interaction
lntrasystemic interaction
Accessibility guideline
standard of usability
design principles
Model of User
Image of System
Expected interaction
Real interaction
SYSTEM
ERRORS
PROBLEMS
Match between Errors and Problems
User UEMs
-
Accessibility
-
Usability
-
Satisfaction
SUBJECTIVE-ORIENTED
MEASURE OF DISTANCE
Expert UEMs
Conformance of
accessibility and usability
Experience,
accessibility guideline,
standard of usability
OBJECTIVE-ORIENTED
Evaluator's mental model
FIgUre 15.4
The role of the evaluator's mental model from the perspective of the UX evaluation: The designer's mental
model is embodied in the system by the conceptual model. The developer designs the system in relation to his
or her experience, representation of knowledge, etc. The designer, taking into account standards and guide-
lines, images an expected interaction according to the user model. The real user applies their mental model
in the interaction with the image of the system, including the manual and other information sources such as
the Internet. The user in the “real interaction” experiences problems whereas the designed system contains the
errors. The evaluator mental model is involved in the evaluation using the UEM to observe the object and the
subject and measure the distance between the designer's and the user's mental models.
