380 likes | 593 Views
2. Events and Decisions. Reactive. Adaptive. Generative. Increasing leverage. A Systems Perspective. 3. A systems view stands back just far enough to...Deliberately blur discrete events into patterns of behaviorDeliberately move from a focus on individual decisions to a focus on policy structure.
E N D
1. 1 Tools for Systems Thinkingand Modeling Dynamics: Graphs over time
Structure: Causal-loop Diagrams
2. 2 A Systems Perspective
3. 3 “Distancing...”
4. 4 The Systems Perspective
5. 5 Dynamic Thinking Define problems in terms of graphs over time.
Graph important variables
Graph historical data
Graph anticipated dynamics
Graph preferred dynamics
Use these to focus systems thinking and modeling
6. 6 Unemployment (%)
7. 7 New York City Populations
8. 8 Percentages of high school grads completing college, by ethnicity
9. 9 Unemployment & Welfare in Dutchess County, NY
10. 10 New York State K-12 Public Education Expenditures per Pupil
11. 11 Strive for Dynamic Insights
12. 12 So you’re getting more education…
13. 13 The Systems Perspective
14. 14 System Structure
15. 15 Causal Diagrams
16. 16 Polarities of Causal Links
17. 17 Definitions of Link Polarities All words phrases are expressed as quantities that have a clear sense of increase or decrease.
No verbs — the action is in the arrows. An increase in A makes B greater than it would have been without the change; a decrease in A makes B less .
18. 18 Examples
19. 19 Feedback Loops A feedback loop exists when decisions change the state of the system, changing the conditions and information that influence future decisions.
20. 20 The Joy of Feedback
21. 21 The Joy of Feedback
22. 22 No — it’s more like the life cycle of the famous scientist
23. 23 Examples of Feedback Loops
24. 24 Two kinds of feedback loops Reinforcing loops
self-reinforcing
growth producing
destabilizing
accelerating
even number of –’s
Symbolized by Counteracting loops
balancing
goal seeking
stabilizing
compensating
odd number of –’s
Symbolized by
25. 25 Examples of Reinforcing Loops
26. 26 Reinforcing Feedback in the Newspaper
27. 27 Reinforcing Feedback in the Newspaper
28. 28 Reinforcing Feedback in the Newspaper
29. 29 Examples of Balancing Loops
30. 30 What are these loops, and what stories do they tell?
31. 31 Tips for Determining Link and Loop Polarities For each link, determine the effect of an increase in the variable at the tail of the arrow:
If the variable at the head increases, assign a plus.
If the variable at the head decreases, assign a minus.
For each loop, count the number of negative signs:
An even number of negative links is a reinforcing (R) loop.
An odd number of negative links is a balancing (B) loop.
Most important: For each loop, tell a self-reinforcing or balancing/counteracting story, and check that the story matches the loop polarity.
32. 32 Linking Feedback Structure and Dynamic Behavior Linking causal loop thinking with graphs over time
33. 33 World Population (billions)
34. 34 Self-reinforcing processes in world population growth
35. 35 Typical Reinforcing Loop Behavior
36. 36 Typical Counteracting Loop Behavior
37. 37 Typical Counteracting Loop Behavior
38. 38 Summary of Structure and Behavior Reinforcing loops are responsible for accelerating growth, accelerating decline, or traps due to inertia
Counteracting loops are much more prevalent but often less obvious; they balance and adapt
Counteracting loops can compensate for policy initiatives and defeat intended effects
Combinations of reinforcing and counteracting loops are responsible for all the complex dynamics we create in our complex systems.