Chapter 7: Decision Making Wickens

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Chapter 7 Decision MakingWickens

• IE 8541 Intelligent Decision Support Systems

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Plan for Today

• Discuss decision making
  Chapter 7, Wickens
• Methods Paper prototype exercise.

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Decision-making Scenario

• Resources
• Anesthesiology team, 4 MDs
• 2 operating rooms
• Needs
• 5 urgent procedures
• Possible emergency procedures
• Decision ?
• Allocate 3 MDs for 5 procedures, leave one to
  attend to emergencies,
• Allocate 4 MDs for 5 procedures, and hope no
  emergencies arrive.

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Decision Making

• A task in which
• A person must select from a number of
  alternatives,
• There is relevant information available
  (situation awareness, SA)
• The timeframe is relatively long (more than 1
  sec),
• Choice is associated with uncertainty, risk.

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Types of Decision Models

• Normative what people should do (e.g.
  rational models of decision making.)
• Descriptive what people actual do.

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Normative Decision Making Models

• Also called multi-attribute utility theory or
  multi-criteria decision making (MCDM) methods.
• Most follow the pattern of
• Assigning a value or utility score to each
  alternative
• Overall utility score is a sum of components
  value scores for several attributes (or criteria)
• Each attribute is weighted by its importance.

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Issue

• Many choices have different value to different
  people.
• Subjective expected utility (SEU) worth of each
  component is subjective, determined by each
  person.

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How consistent are people at ranking alternatives?

• 20 university faculty were asked to rank order 4
  alternatives.
• They were asked to rank order a second set of 4
  alternatives (where were identical to the first
  set, in disguise).
• Only half of their rankings were the same, on
  average.
• Conclusion People can become more consistent if
  formal decision making methods are used.

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Other decision making methods

• Dominance An alternative dominates others is
  the same or better than all other alternatives
  for all criteria.
• Lexicographic first compare most important
  criteria. If none dominate, then compare second
  most important criteria, etc.

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Pros and Cons Lexicographic Method

• Most appropriate when one or two of the
  properties out weighs all the others
• Least appropriate when many properties are all of
  equal importance

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Naturalistic Decision Making

• How people really make decisions in messy,
  uncertain, rapidly changing environments.
• There is not always time for careful
  consideration of each criteria for each
  alternative.
• A decision process depends on limited cognitive
  resources.

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Heuristics and Biases

• Attention to limited number of cues
• First cues get greater weight primacy effect.
• Inattention to later cues everything seen as
  justifying initial hypotheses (danger of option
  generating DSSs brittleness effect.)
• Cue salience perceptually salient cues that
  capture attention are given more weight .. (This
  is why the squeeky wheel gets the oil )
• Overweighting people may treat all cues as equal
  too much weight given to unreliable evidence.

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Improving Human Decision Making

• Task re-design
• DSSs (tools for decision making). Cognitive
  prostheses Roth, 1987.
• Training