Using System Dynamics to Model Risk Perception and ... System Dynamics to Model Risk Perception and...

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Using System Dynamics to Model Risk Perception and Communication in Response to Threat Alan Brothers, PNNL and Oleg V. Pavlov, WPI

Transcript of Using System Dynamics to Model Risk Perception and ... System Dynamics to Model Risk Perception and...

Page 1: Using System Dynamics to Model Risk Perception and ... System Dynamics to Model Risk Perception and Communication in Response to Threat. Alan Brothers, PNNL. and . Oleg V. Pavlov,

Using System Dynamics to Model Risk Perception and

Communication in Response to Threat

Alan Brothers, PNNLand

Oleg V. Pavlov, WPI

Page 2: Using System Dynamics to Model Risk Perception and ... System Dynamics to Model Risk Perception and Communication in Response to Threat. Alan Brothers, PNNL. and . Oleg V. Pavlov,

Mathematical Modeling in Social Science

Physical sciences as ideal for social scienceSocial science evolved from case studies

Margaret MeadClark Hull

Advantages of modelsForces precisionHypothesis testing

Work at PNNL in Motivation and IntentAid analysts in assessing group propensity for violenceModel social science theories after the fact of their constructionCan serve as a blue print for collaboration between modelers and social scientists in research on Dynamics of Risk Perception.

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System Dynamics

Used to model complex systems in which there are feedback loopsThere are two types of variables:

Stocks or levels; e.g. inventory, perceived riskFlows or rates; e.g. production rate, deaths per thousand per year.

Invented by Jay Forrester at MITUsed to model social systems including business models, ecological systems, diffusion of fear following catastrophe (Burns and Slovic)

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The System Dynamics Paradigm

Emphasizes insight and understanding over predictionPredicts patterns of behaviorPoint predictions are more problematic

Concept of cause and effect is central to modelTypically build causal loop diagrams firstData can be used to establish specific functional relationships

Verification and Validation is more than fitting dataClarity of purpose—fulfills intended functionDocumentation—transparencyConceptually valid—relationships among variables are theoretically and empirically compellingBehaviorally valid—behaves in a reasonable mannerData consistency

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The System Dynamic Method

MethodIdentify major factors.Identify cause and effect relationships.Characterize the relationships as direct or inverse.Diagram relationships.Build stock and flow computer model.Validate the model.Analyze behavior of system through simulations.

Value: It shifts the focus from one aspect of a system to the behavior of the system as a whole.

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Some Simple Loops: Reinforcing or Positive Loop

ExerciseAmount

Fitness Level

Pleasure ofExercise

+

++

R

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Some Simple Loops: Balancing or Negative Loop

PreditorsPrey-

B

Food forPreditors+

+

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Common Modes of Behavior in Dynamic Systems

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Exponential decline

Asymptotic decline

Exponential growth

Asymptotic growth

Stock

Overshoot and collapse behavior

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Note: Time axes for top and bottom graphs differ.Source: Bahn and Flenley (1992, p. 174).

Estimated population and tree cover of Easter Island

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Generic structure that generates overshoot and collapse

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Monthly IED incidents in Iraq (JIEDDO)

• Build model based on subject matter expertise that is consistent with data.

A System Dynamics model of IED Effectiveness

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Two Types of SD Models: (1) Causal Loop Diagram (CLD)

Percent PopulationUnder Control

IED Effectiveness

+

R1

Increased CoalitionPatrols+

B1

IED Soph istication

+

ControllingPopulationR2

TechnicalImprovements

-

B2

Gaining Trust

Technical CounterMeasures

+

-

B4

TechnicalResponse

Coalition to CivilianCasualty Ratio

+

Cleared andIneffective IEDs

+

-

Clearing IEDs

Deployed IEDs

+

Rollups+

-

B3

CatchingInsurgents

Recruitment+

+

R3Recruitment

++

+

+

R4

IED Race

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Two Types of Models: (2) Stock and Flow Model

Infection Module Escalation Module

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A New Paradigm of Risk Perception

Risk perception had been staticThe focus of past research has been on factors that influence perceptions of risk and how layman conceptions differ from experts.Perception of risk following terrorist events or natural disasters evolve quickly as events unfold. There is a need for dynamic models of how risk perceptions evolves following catastrophic events and how it is impacted by government actions and the media.

System dynamics is well suited to model these changes over time

complex interactions and feedback loops.

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Dynamic Hypothesis

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Model Sectors

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The Mass Media Sector

Alternativ e Cov erage

Ev ent Cov erage

Increase in Cov erage

~

HazardEv ent Signal

~Ef f ect of Hazard Ev ent on Cov erage

~ Ef f ect of Signal on Cov erage

Ty pical Duration ofCov erage

Time to Increase Cov erage

Decrease in Cov erage

Desired Cov erage

Max Cov erageof An Ev ent

Gap in Cov erage

Fractional Loss in Economic

Activ ity~Ef f ect of Economy

on Cov erage

Mass Media

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The Risk Perception Sector

~

Ef f ect of Signal on Fear

Fearf ulIncrease in Fearf ul

Decrease in Fearf ul

Management Competency

TrustIncrease in Awareness

Max Fraction of Fearf ul

~Ef f ect of

Competency onFear Adjusted Fraction

of Fearf ul

Not Fearf ul

Signal

Time to Calm Down

~Ef f ect of

Trust on Fear

Risk Perception

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Base Run

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High and Low Values of Trust

High Trust

Low Trust

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Amplification of the Signal

Signal = 0.2

Signal = 0.5

Signal = 1.0

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What Causes Dynamics?

All dynamics are driven by –

Feedback processesAccumulation processes

The generic behavior modes can be produced by relatively simple generic structures.

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Exponential growth: Structure and behavior

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Goal seeking: structure and behavior

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Oscillation: Structure and behavior

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S-shaped growth with overshoot and oscillation:structure and behavior

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S-shaped growth:

structure and behavior