what-when-how
In Depth Tutorials and Information
improved by identifying the points of failure through application of various condi-
tions of threat.
Risk analysis is a widely studied topic. In order to assess risk, it must first be
defined. Risk is generally defined as the combination of the occurrence probability
of damage and its gravity. Likewise, risk assessment is defined as the series of logical
steps used to systematically examine the risks associated with an operational system
[15]. But the difficulty in determining or defining which steps should be taken to
analyze the system increases as the complexity of the system increases. his is the case
for applying risk analysis to sociotechnical systems, where this system is defined as
one in which influential interactions occur between humans and some organizational
infrastructure. Sociotechnical systems are inherently multi-dimensional and highly
complex. A means of defining the method for performing risk analysis to a given
sociotechnical system is not necessarily applicable to other systems. Each application
is typically unique and highly dependent on the domain of interest.
Different studies addressing the difficulty of applying risk analysis to a socio-
technical system are summarized in this chapter. Each describes the complexities
that arise in accurately representing the system of interest, as well as, consideration
of identifying all contributing factors.
9.2 BayesianBeliefNetworkApproach
forRiskAnalysis[5]
It is widely accepted that the human element plays a major role in most accidents
involving modern ships. he Transportation Safety Board of Canada (TSB) [2]
concluded that 74% of accidents at sea are attributed to human error whereas only
1% is attributed to technical failures. he chart in Figure 9.1 displays the results
of these statistics. Of the cases involving human error, 45% of accidents are attrib-
uted to the pilot or master's misjudgment, 10% to a lack of communication, 10%
to inattention by the officer on watch, 13% to inattention of the pilot, and 9% to
misunderstanding [2]. he chart concerning the breakdown of human error cases
is displayed in Figure 9.2.
In addition to the statistics provided by the Transportation Safety Board, data
from Lloyds Informative Maritime Service [3] help to support the link between
accidents and human error. he statistics claim that half of all maritime accidents
are attributed to excessive speeds and an uncorrected course with respect to the
traffic in the sea zone.
Ensuring safety for maritime transport would require a more in-depth under-
standing of the human role and its contribution to accidents. Even so, it seems
there are additional factors that need to be considered in the analysis of risk. he
Zeebrugge incident [4], where a passenger ship capsized, was reportedly a result of
“systematic change in the organizational behavior of operators under the influence
