The Type of People Involved in a Cognitive
Walkthrough
The inspection team for a cognitive walkthrough
(CW) can be as few as one and as large as is realistic given the system
and the organization. Having only one person performing the walkthrough
undoubtedly reduces costs, but greatly increase turnaround time and the
potential for validity problems (see question
4 on internal and external validity). Even if the individual
is extensively trained in the CW method, it is recommended that at least
one other person participates in the process to counter the impact of only
one person inspecting the interface. By allowing multiple people
to check each stage of the process, a more thorough and detailed inspection
can be achieved. Also, having more than one person involved allows
a multitude of different perspectives to develop and will result in a richer
description of the problems and more innovative interpretations.
It is not recommended that the group exceed more
than 3-5 people as it is felt that the tradeoff of increased innovation
and thoroughness is balanced with decreased efficiency. Having many
people try to account for problems can be in of itself problematic because
the amount of time to reach consensus presumably increases as the group
size goes beyond this range.
The issue of whether usability specialists are needed
on the CW team is important from both a cost and time perspective.
Research indicates that although UI specialists are not required, successful
execution of the CW requires a deep understanding of the theory.
In order to ensure adequate theoretical knowledge, suitable training programs
are required to successfully apply the theory in the CW (Polson, Wharton,
and Rieman; 1990).
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