COMP 3530/6353

Systems Thinking in PracticeBarry Newell and Katrina Proust

Systems Thinking

What is systems thinking?

In this course we take ‘system thinking’ to mean thinking about the way that the parts of a system interact to influence each other’s behaviour.

We are particularly concerned with ‘feedback’ and its effects in complex adaptive systems.

Systems Thinking

We use the term ‘feedback’ to refer to cause-effect loops.

In a cause-effect loop a change in any one variable propagates around to loop to either amplify or counteract the original change.

Why is systems thinking important?

The behaviour of a complex adaptive system emerges from feedback interactions between its parts.

Feedback systems can react to policy interventions in surprising ways. This is true even when you are dealing with systems that have simple structures.

Systems Thinking

Basic Systems Principle

In a complex system all actions

produce a spectrum of outcomes. The

expected outcomes may or may not

occur; the unexpected outcomes

always occur.

Systems Thinking

Why is systems thinking important?

You cannot understand or anticipate the behaviour of a complex system without understanding and thinking about feedback.

Note that ‘systems thinking’ always begins with ‘feedback thinking”.

Systems Thinking

Systems Thinking

Systems thinking requires an understanding of feedback:

There are just two types of feedback – reinforcing and balancing.

When you want change

When you want stability

Reinforcing(positive)Feedback

Helps Hinders

Balancing(negative)Feedback

Hinders Helps

Reinforcing (or positive) feedback amplifies change

Balancing (or negative) feedback counteracts change

Feedback

The Complexity Dilemma

1. A feedback system is a set of parts (elements, actors) that interact to constrain each other’s behaviour. A software development team is a good example.

2. The behaviour of such a system emerges from the interactions between its parts.

3. Therefore, you can’t optimise the behaviour of the system by optimising the behaviour of the parts taken in isolation.

4. You have to study the system as a whole.

5. But, when you try to do this, you are overwhelmed by the complexity of the system.

Escaping the Complexity Dilemma

One way to escape the complexity dilemma is to look for shared features or attributes between things which, at first sight, seem to be very different.

For example, if a number of apparently disparate behaviours can be shown to be just different versions of a single behaviour, there can be a significant reduction in the apparent complexity of the observed world.

Activity 1

What do these policy approaches have in common?  1. Constructing freeways 2. Substance abuse 3. Dependence on refrigerated air conditioning 4. The war on drugs 5. Low-cost housing for urban renewal 6. Constructing flood-control levees 7. Engineering the climate 8. Using miticides to protect bee colonies 9. Spraying ragweed with broad-spectrum herbicides*10. Using “mould killer” in bathrooms*11. Introducing shrimp to feed freshwater salmon*12. Planting wheat on the Great Plains, USA*

Activity 1

1. Working in a group of 4 consider the policy approaches listed in Handout A.

2. What do these policies have in common?

3. Discuss this question in your group and be prepared to present your insights to the whole workshop.

Structure Behaviour

– The behaviour of a system is driven by its

‘feedback structure’.

– There are a number of relatively simple feedback

structures that are seen in a wide range of

contexts, that have characteristic behaviours, and

that have the potential to dominate urban-health

outcomes.

– These structures are called System Archetypes.

The Ragweed Problem

The Ragweed Problem

But … leads to more ragweed next year. Why?

The Ragweed Problem

The Mould Problem

It’s habit forming

CHOICEMagazine2012

The Mould Problem

Spencer et al. 1991, BioScience, 41, 14-21.

Salmon and Shrimp

Salmon and Shrimp

Wheat on the Great Plains

Generic Structure

Fixes That Fail

System Archetype

Characteristic Behaviour

Fixes That Fail

SystemArchetype

A system archetype is a simple feedback structure that has a characteristic pattern of behaviour.

System Archetypes

System archetypes are generic. A single archetype can be used to explain the behaviour observed in many contexts.

Popularised by Peter Senge (1990), who called them Nature’s Templates.

– A systems-thinking approach that uses system

archetypes does not, of course, yield a full,

predictive model of system behaviour.

– But it can provide an initial view of feedback

structures that have the potential to dominate

the behaviour of the system.

– In many contexts system archetypes are

critically important because they focus attention

on the impacts of policy and management

decisions.

System Archetypes

ProblemSymptom

The problem is not the Ragweed infestation but the lack of perennial vegetation cover. Leverage Point

Leverage Points

Fixes That Fail

Leverage Points

Activity 2

Working in your groups:

1. Select a policy from those numbered 1 to 8 in the handout list.

2. Develop a Fixes that Fail diagram that explains why your selected policy might fail in the long term.

3. Present your diagram and your analysis of the reasons why policy failure is possible.

4. Can you identify potential leverage points for change?