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Step Two: Determine the Causal Relationships
Each time we develop an elemental causal set, we enrich our
understanding of the problem and increase the number of causes, each
of which may provide an opportunity to act upon and thus prevent the
problem from occurring again.
The best solutions are usually associated with conditional causes,
partly because of our greater ability to control conditional causes, whereas
people or action causes are less predictable.
Sometimes causes are noncauses. That is, they are nonactions
or nonconditions. For example, the action in Figure 5.7 states that the
valve was not energized—a nonaction, but listed as an action cause to
distinguish it from a conditional cause. The same can occur with conditions.
We could have “no firefighters on duty” as a conditional cause.
Sometimes the causal elements create a close-coupled feedback
loop like Figure 5.7. In this causal element from the Deepwater Horizon
Well incident we see that the solenoid valve could not be energized
because of the condition of an electrical fault in the solenoid coil, but
that is a conditional cause and we need a corresponding action cause, but
there was no action, just a nonaction of “Not Energized.” These types of
causal sets are difficult for beginners to recognize, but are shown here to
help you see different permutations that actions and conditions can take.
They are always there, but not always easy to identify because we have
never been taught to think causally.
There are two basic types of feedback loops, positive and negative.
Action
Not Energized
Caused
By
Primary Effect
Solenoid Valve
Failed To Open
Caused
By
Condition
Electrical
Coil Faults
Feedback Loop
Figure 5.7.
Negative Actions and a
Feedback Loop
Positive feedback in a system is where the increase in a given variable
or cause produces a further increase in that variable or cause. The growth
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