Risky Business
Decision Theory and Implications for Health & Safety
Petroleum Safety Conference - 2014; Ryan Campbell, B.Sc., CRSP
Behaviour Based
Safety
✤
Old model, Bird
published in 1986
✤
Stop, Think, Act
✤
New ideas on how we
think
behaviour
noun
the way in which one acts or conducts
oneself, esp. toward others.
• the way in which an animal or person
acts in response to a particular situation
or stimulus.
decision
noun
a conclusion or resolution reached after
consideration.
• the action or process of deciding
something or of resolving a question.
Old Hardware,
New Software
✤
Behaviourally modern humans
evolved ~50,000 years ago
✤
Industrial revolution 1760-1840
✤
Old brains making decisions in
new environments
01
Old Hardware,
New Software
✤
It’s so easy a caveman can do it
✤
Our brains are still making
decisions like we’re hunters and
gatherers
✤
What worked 3,000 years ago
might not work today
01
System 1: listen to your gut
✤
Fast
✤
Low effort
✤
Takes shortcuts
✤
No voluntary control
System 2: stop and think
✤
Time intensive
✤
High effort
✤
“Conscious” thinking
✤
Logical & analytical
Decision =
Evaluation of outcomes &
probabilities of occurrence
and choosing between them
✤
Outcomes have subjective values
(e.g. gain, loss, benefit, injury)
✤
Probabilities are determined and
weighted
✤
Old brains making decisions in new
environments
Decision: a choice between
different possible actions
✤
Actions have outcomes
✤
Outcomes have subjective
values
✤
Outcomes have probabilities
✤
A purely rationale choice would
only be a function of value and
probability
01
Problems with
Probabilities
Consider the following choice:
a) 0.1% chance to win $5,000
b) $5 for sure
01
Problems with
Probabilities
Consider the following choice:
a) 0.1% chance to win $5,000 (72%)
b) $5 for sure (28%)
Kahneman and Tversky, 1979
01
Problems with
Probabilities
Consider the following choice:
a) 0.1% chance to lose $5,000
b) lose $5 for sure
Kahneman and Tversky, 1979
01
Problems with
Probabilities
Consider the following choice:
a) 0.1% chance to lose $5,000
(17%)
b) lose $5 for sure (83%)
Kahneman and Tversky, 1979
01
Problems with
Probabilities
✤
In H&S, probabilities are mainly
subjective
✤
We weight probabilities during
decision making
✤
Extremely low and high
probabilities are overweighted
✤
Low to moderate probabilities
are underweighted
01
Problems with
Probabilities
✤
Probabilities are impacted by
our ability to recall similar
events - Availability Bias
✤
Vivid and catastrophic events
influence us more
✤
Prime workers with incidents to
influence their decision weights
01
Kahneman and Tversky, 1979
01
Loss Aversion
Consider the following choice:
a) 80% chance to win $4,000
b) $3,000 for sure
N=95
Kahneman and Tversky, 1979
Kahneman and Tversky, 1979
01
Loss Aversion
Consider the following choice:
a) 80% chance to win $4,000 (20%)
b) $3,000 for sure (80%)
Risk AVERSE
Kahneman and Tversky, 1979
Kahneman and Tversky, 1979
01
Loss Aversion
Consider the following choice:
a) 80% chance to lose $4,000
b) Lose $3,000 for sure
N=95
Kahneman and Tversky, 1979
Kahneman and Tversky, 1979
01
Loss Aversion
Consider the following choice:
a) 80% chance to lose $4,000 (92%)
b) Lose $3,000 for sure (8%)
Risk SEEKING
Kahneman and Tversky, 1979
Kahneman and Tversky, 1979
01
Loss Aversion
✤
We don’t like losing
✤
It is the change, the idea of
gaining or losing that matters,
not the end state
✤
The safe decision needs to be
believed to be the gain
Kahneman and Tversky, 1979
✤
Additional costs are sure losses
compared to increased
likelihood of incidents
01
Framing
✤
A decision box
✤
Physiology
✤
Emotions
✤
Fatigue
✤
How WE present decisions
01
There has been an outbreak of a deadly
disease. Choose one of the following treatment
options:
If Program A is adopted, 200 people will be
saved.
If Program B is adopted, there is a 1/3 chance
that 600 people will be saved and a 2/3 chance
that no people will be saved
Tversky and Kahneman, 1981
01
There has been an outbreak of a deadly
disease. Choose one of the following treatment
options:
If Program A is adopted, 200 people will be
saved. (72%)
If Program B is adopted, there is a 1/3 chance
that 600 people will be saved and a 2/3 chance
that no people will be saved (28%)
N=152
Tversky and Kahneman, 1981
01
There has been an outbreak of a deadly
disease. Choose one of the following treatment
options:
If Program C is adopted, 400 people will die.
If Program D is adopted, there is a 1/3 chance
that nobody will die and a 2/3 chance that 600
people will die.
Tversky and Kahneman, 1981
01
There has been an outbreak of a deadly
disease. Choose one of the following treatment
options:
If Program C is adopted, 400 people will die.
(22%)
If Program D is adopted, there is a 1/3 chance
that nobody will die and a 2/3 chance that 600
people will die. (78%)
N=152
Tversky and Kahneman, 1981
01
Framing
✤
It changes everything
✤
Be depressing
✤
Play to emotions
✤
Use real numbers and not
percentages
✤
Schedule high risk work for after
a break
01
Nudging
✤
Nudges gently push people to
better (safer) decisions
✤
Not widely used, yet
✤
Organization and site-specific
✤
People still have free choice,
but the choice is structured
01
Nudging
✤
The most famous nudge of
them all….
01
Maybe more
relevant….
✤
Lake Shore Drive, Chicago
✤
Signs, straightening, nothing
prevented accidents.
✤
Post Nudge: 36% fewer crashes
✤
Influence perception, cause real
change
01
Health & Safety - Moving Forward
✤
Behaviour based safety is a beginning, not an end
✤
Decision theory; psychology; physiology, etc. All are
important to help ensure worker safety
consilience
noun
agreement between the approaches to a topic of different academic
subjects, esp. science and the humanities.
“Human error is not the cause but the effect. Whatever the
label (loss of situational awareness, inadequate resources,
even complacency) human error can never be the conclusion
of your investigation. It is the starting point.”
–Sidney Dekker