Teaching Systems Thinking in Spreadsheets

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Teaching Systems Thinking in Spreadsheets

• Mohammad Mojtahedzadeh
• Attune Group, Inc
• Deborah Upton
• Stonehill College

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Modeling Spectrum
Exposé
System Dynamics

• Spreadsheet

Simple Manipulation
Complex Formulation
Build on Simple manipulation to arrive at Complex
formulation
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Modeling Spectrum
Exposé
System Dynamics

• Spreadsheet

Simple Manipulation
Complex Formulation

• Hidden relationships

• Visualization of structure

• Local in time and space

• Global in time and space

• One way linkages

• Circular Causality

• Stock-and-Flow

• Mathematical Nonlinearity

• Data-Point Nonlinearity

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The Spreadsheet Approach
Hidden relationships
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The Spreadsheet Approach
Hidden relationships

• Makes it difficult to
• understand,
• analyze and, communicate

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Exposé in MS Excel
Tree Diagrams of Precedence
make the connections among the CELLS visible
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The Spreadsheet Approach
Local in Time and Space

• Working with numbers (not equations)
• One relationship, one time period
• No clear model boundaries

. makes it easy to master!
. but inadequate for modeling complexity!
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The Spreadsheet Approach
Local in Time and Space

• 1000 95.26 ?

• Purchases (Jan)

Savings (Jan)
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From cell reference formulas to equations

• Translate cell reference formulas to equations

• Savings (t) Savings (t - 1) - Purchases

1,000

• 95.26

February
January

• Reconstruct the structure

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Exposé in MS Excel
Tree Diagrams of Causal Drivers
make the connections among the VARIABLES visible
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Exposé in MS Excel
Two distinguished tree diagrams
Tree Diagrams of Causal Drivers
Tree Diagrams of Precedence
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The Value Proposition
Can we build on what people know?


Global (interconnected)
System Dynamics
Complex Issues
Spreadsheet
Local (isolated)
Simple Issues
Short term
Long term
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The Value Proposition
From Numbers to Equations and back again

• Exposé allows the user to interact with Numbers
  and Equations any time in the process of modeling
  
• Sometimes it might be easier to start with
  Numbers and then move to Equations

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Example From Numbers to Equations and back again
Sometimes, wouldnt be easier to start with

• 1000 95.26 ?

• Purchases (Jan)

Savings (Jan)
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Example From Numbers to Equations and back again
.. in order to arrive at..?
Savings Integ( purchases, 1000)
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The Spreadsheet Approach
One way linkages

• Lack of focus on
• integration point and
• feedback processes
• makes spreadsheets inadequate to model
  dynamic systems

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Exposé in MS Excel
Make integration points visible
Launch Exposé with Examples from the book
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Exposé in MS Excel
Circular Causality
Identify and work with feedback processes
Launch Exposé with Examples from the book
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Exposé in MS Excel
Allows data-point non-linearity
Launch Exposé with the MARKET GROWTH MODEL
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Exposé in MS Excel
Do what if analysis more often
Launch Exposé perhaps with Market growth model
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Not The End. Just The Beginning