Transcript Tutorial 3: Case Study “Act of God” “The Wizards of Wall Street”

Tutorial 3:
Case Study
“Act of God”
“The Wizards of Wall Street”
SY DE 142 – May 31st, 2004
Introduction to Human Systems Engineering
Waterloo, Ontario, Canada
Outline
 Case Study: “Act of God”
 Discussion on “Act of God”
 Case Study: “The Wizards of Wall Street”
 Discussion on “The Wizards of Wall Street”
Act of God
Overview
 Time: July 13 and 14 1977
 Place: Manhattan, New York, USA
 Synopsis:
Power Failure in Manhattan
Collapse of the Con Edison Electric System
Act of God
Causal factors
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Not showing needed information on the console
No sense of precariousness of the infrastructure
No sense of time dynamics
No causal connections between parts of network
No overview of network state
Independent displays with no integration of information
Couldn't figure out the original source of the problem
Poor communication
Failure to take necessary actions in time
Act of God
Results
Lightning strike to a power line causes a
cascade of events eventually blacking out
New York City
Act of God
Discussion
 In the Act of God, Bill must make several
decisions affecting the distribution of electrical
power to New York City. Describe the three
different categories of cognitive biases and
discuss how they may have affected Bill's
ability to make effective decisions on the night
of the lightning strike in the case study. Be sure
to give examples from the case study.
Cognitive Biases in Act of God
Case Study
 Input or Cue Biases
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Bill weighted the earliest incoming information
heaviest.
He did not search very far for information,
including not going to the room that had the right
display.
Biases in Hypothesis Generation
and Selection
 Biases in Hypothesis Generation
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Bill had one hypothesis and stuck to it
He did not come up with new ideas
 Biases in Evaluation and Selection
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Bill rejected Kennedy's alternative, even though
Kennedy was right.
Plan generation and Action choice
 Biases in Action Selection
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Most people argued that he talked on the phone
rather than taking the necessary actions to correct
the situation, therefore demonstrating not taking
action.
System Interactions
 In the Act of God, a lightning strike hits two
power lines that ran on the same transmission
tower. What kind of system interaction is this?
System Interaction in Act of
God case study
• common mode interaction , why? (see Accident
Analysis and Fault Trees)
• One component services two or more parts.
2 lines and one transmission tower
The Wizards of Wall Street
Overview
 Time: Wednesday, March 25, 1992
 Place: Wall Street, New York, USA
 Synopsis:
Pandemonium on Financial Market
Loss of the Company
The Wizards of Wall Street
Causal Factors
 Misunderstanding of 11,000,000 shares
versus dollars
 Poor Interface Design
 Time pressure and stress
 Context of large “sale on close” orders
The Wizards of Wall Street
Results
Computerized trading system allows a
trading clerk to make a huge error setting off
a volatile round of selling
The Wizards of Wall Street
Discussion
 What type of human error is presented in this
case study. Give an example that supports
your answer.
Human Error in Wizards of
Wall Street
 Mistake: wrong goal and intention leading to wrong
action (he sold 11M shares of stock instead of 11M
dollars of stock)
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Why?
Rapid conclusion without all information being present
Misunderstood the order
 However – if he did realize that it was 11M dollars
and only input data in the wrong field, this would
have been a slip type of error