Introduction to System Thinking Hendrik Stouten 1‐day Training Course @ Auckland Regional Council July 5 th , 2012
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Introduction to System Thinking
Hendrik Stouten1‐day Training Course @ Auckland Regional Council
July 5th, 2012
Linear versus Feedback Thinking
A B C
Linear thinking
Linear versus Feedback Thinking
Cause
Too many Cars Too many Accidents Make cars more expensive
Effect Solution
Not enough Sales Downfall in profit Hire more sales people
Linear thinking
Linear versus Feedback Thinking
Cause Effect Solution
Feedback Loop 1
Feedback Loop 2
Cars Accidents Price cars
Feedback Loop 1
Feedback Loop 2
Feedback thinking
Types of feedback loops
• How many types of feedback loops do exist?
A: Between 0 and 5 typesB: Between 5 and 10 typesC: Between 10 and 20 typesD: Between 20 and 30 typesE: Over 30 types
The positive feedback loop
State 1
State 2
+
R
+
Name of loop
Generic Structure & Generic Behaviour
The positive feedback loop
Bank Account
Interest
+
R
+
Money makesmoney
Example: My bank account
The positive feedback loop
Sales
Sales people
+
profit+
+
R
Growth throughsales
Example: The Sales loop
The positive feedback loopExample: The Urban Water supply Loop
Source: Mirchi, A., Madani, K., Watkins Jr. D. & Ahmad, S. (2012) Synthesis of System Dynamics Tools for Holistic Conceptualization of Water Resources Problems. In: Water Resource Management 26, 2421‐2442.
The negative feedback loopGeneric Structure
Desired State
Current State
Gap Action
+
-++B
Name of loop
The negative feedback loopExample: Meeting sales target
Sales Target
Total Sales
Sales Gap Sales Force
+
-++B
Meet SalesTarget
The negative feedback loopExample: Meeting sales target
Source: Mirchi, A., Madani, K., Watkins Jr. D. & Ahmad, S. (2012) Synthesis of System Dynamics Tools for Holistic Conceptualization of Water Resources Problems. In: Water Resource Management 26, 2421‐2442.
Causal loop diagrams (CLDs)
Source: http://bosquesalvador.wikispaces.com/Term+Project
Causal loop diagrams (CLDs)
Source: http://www.systemdynamics.org/DL‐IntroSysDyn/feed.htm
Causal loop diagrams (CLDs)
Source: http://www.agate‐inc.com/cld_ex.html
Causal loop diagrams (CLDs)
Source: http://joquico‐khoo.wikispaces.com/Term+Project
Guidelines for CLDs• Based on causation not correlation• Variable names should be noun or noun phrases• Variable names should have a clear sense of direction• Label link and loop polarity• Name your loops• Indicate important delays in causal links• Make the goals of negative loops explicit• Distinguish between actual and perceived conditions• Use the right level of aggregation• Use curved lines• Make important loops follow circular/oval paths• Minimize crossed lines• Do not put all the loops into one large diagram
Source: Sterman, J. (2000) Business Dynamics: Systems thinking and modeling for a complex world. McGraw Hill.
The End
Summary of what we have covered so far:
(1) Linear versus feedback thinking(2) Two types of feedback loops: positive and negative feedback loops
(3) Causal Loop Diagrams (CLDs)(4) Guidelines for drawing neat CLDs
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