Tutorial 3: Case Study

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Tutorial 3Case Study

• Act of God
• The Wizards of Wall Street
• SY DE 142 May 31st, 2004
• Introduction to Human Systems Engineering
• Waterloo, Ontario, Canada

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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

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Act of GodOverview

• Time July 13 and 14 1977
• Place Manhattan, New York, USA
• Synopsis
• Power Failure in Manhattan
• Collapse of the Con Edison Electric System

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Act of GodCausal factors

• 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

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Act of GodResults

• Lightning strike to a power line causes a
  cascade of events eventually blacking out New
  York City

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Act of GodDiscussion

• 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.

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Cognitive Biases in Act of God Case Study

• Input or Cue Biases
• 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.

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Biases in Hypothesis Generation and Selection

• Biases in Hypothesis Generation
• Bill had one hypothesis and stuck to it
• He did not come up with new ideas
• Biases in Evaluation and Selection
• Bill rejected Kennedy's alternative, even though
  Kennedy was right.

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Plan generation and Action choice

• Biases in Action Selection
• Most people argued that he talked on the phone
  rather than taking the necessary actions to
  correct the situation, therefore demonstrating
  not taking action.

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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?

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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

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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

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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

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The Wizards of Wall StreetResults

• Computerized trading system allows a trading
  clerk to make a huge error setting off a volatile
  round of selling

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The Wizards of Wall StreetDiscussion

• What type of human error is presented in this
  case study. Give an example that supports your
  answer.

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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)
• 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