Information Technology Reference
In-Depth Information
System
Description
Suggested
changes
(requirement
s & design)
Error
Analysis
(using human
IP model)
Analyse
Scenario
(e.g., HTA)
Work
Description
Fig. 10.6
The THEA process
teams of people. THEA was therefore adapted and extended to create a new
method, CHLOE. CHLOE takes into account how people collaborate to get work
done, and has been used to analyze errors in Air Traffic Control (Miguel and
Wright
2003
).
10.5 Implications for System Design
We need to consider how people interact with technology in a particular context
when designing systems. Each of the components (people, technology, and con-
text) can give rise to errors, so we need to design systems to take account of this,
and try either to prevent the errors or at least to mitigate their consequences. It is
also vital that we consider the interdependencies between people, technology, and
context, because these can also give rise to errors.
We know that most systems can be described as socio-technical systems, in that
they have social (people-related) components and technological components.
Unfortunately, however, many designers think this means that the system can be
decomposed into a social subsystem and a technical subsystem. In reality, such an
atomistic decomposition is inappropriate, because of the interactions and inter-
dependencies between the system's social and technical components. If these
interactions and interdependencies are ignored, the emergent system behaviors
(including errors) that they give rise to may be overlooked. Many system devel-
opers who claim that they use a socio-technical approach often decompose the
system into social and technical subsystems, and focus most of their attention on
the technical subsystem.
Allied to the decomposition into human and technical components is a tech-
nique called function allocation. When designing a system, you will need to
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