2 June 2021, 08:14

on systems thinking


The behavior of a thing is latent in its structure.

e.g: A Slinky toy rests in a person’s palm and another hand grasps the top of the slinky several coils down. Removing the hand results in the Slinky dropping and then bouncing up and down. The hand did not make the Slinky bounce. The Slinky itself possessed the necessary properties for that specific behavior. Understanding the relationship between behavior helps us understand how poor outcomes happen and how to generate better ones.

“It is a way of thinking that gives us the freedom to identify root causes of problems and see new opportunities.”

A system is an interconnected set of things (people, cells, molecules, components, etc.) that produces a specific outcome over time.

  • A system can be triggered or influenced by external forces.
  • The system’s response to external forces is a characteristic of the system itself (see slinky example).
  • An external force that triggers a system response will likely result in a different outcome when applied to a different system

“The behavior of a system cannot be known just by knowing the elements of which the system is made.”

System Structure

A system consists of three things:

  • Elements
  • Interconnections
  • A function or purpose

e.g: The digestive system

Elements: Teeth, enzymes, stomach, intestines. Interconnections: The physical flow of food, chemical signals to regulate the process. Function: To separate nutrients from food (to maintain and provide energy to the body) and to collect and discard unusable waste.

Systems don’t exist in isolation.

  • Systems can be interconnected with other systems.
  • Systems can be embedded within other systems

Conglomeration: A collection of things that LACK interconnections or function. Example: Sand scattered on a road is not a system

“When a living creature dies, it loses its ‘systemness.’ The multiple interrelations that held it together no longer function, and it dissipates, although its material remains part of a larger food-web system.”

“A system is more than the sum of its parts. It may exhibit adaptive, dynamic, goal-seeking, self-preserving, and sometimes evolutionary behavior.”

The flow of information, from one part to another, is a common way that system interconnections are manifest.

“The best way to deduce the system’s purpose is to watch for a while to see how the system behaves.”

  • Watch what the system does not what is says or advertises itself to be doing.
  • e.g: “If a government proclaims its interest in protecting the environment but allocates little money or effort toward that goal, environmental protection is not, in fact, the government’s purpose.”

Self-perpetuation is an important function for almost every system.

System purposes need not be human purposes nor need they be the intended purpose. It is common for a well-meaning system to result in unintended outcomes and behaviors.

Successful systems keep “sub-purposes and overall system purposes in harmony.”

Changing elements in a system often has the least impact on the overall system behavior. Modifying the interconnections and purpose often results in dramatic or fundamental changes.

“The least obvious part of the system, its function or purpose, is often the most crucial determinant of the system’s behavior.”

System Basics

A stock: This is an element in the system that is accumulated, depleted or stored over time.

e.g: water in a bath, the population of a city, books in a bookstore, money in a bank.

“A stock is the memory of the history of changing flows within the system.”

A stock changes over time based on flow. A flow represents elements entering the system stock as well as elements leaving or being depleted from a system stock.

e.g: For a population, an inflow might be represented by births (these ADD to the population stock). Outflows might be represented by deaths (these result in a reduction in the population stock).

Stock-and-flow diagram: A visual representation of a system that shows inflows, outflows, reinforcing and balancing loops, stocks and interconnections with other systems.

  xxx              ┌────────┐
 x   xxxx          │        │                xxxx
xx      xxx        │ stock  │         xxxx x x  xx
x         x──────► │        │ ──────► xx         x
 xxxxxxxxxx        │        │           xx       x
                   └────────┘            xxxx    xx
           inflow             outflow        x xxxx

System diagrams are simplified representations of the real world “The map is not the territory.”

← on being anti-fragile
on service design →