“Thinking in Systems” (Book Review)

“Thinking in Systems” is a short but pretty dense book about systems thinking. Its author, the late Donella H. Meadows, was an environmental scientist who back in the Seventies started applying the then relatively new tools of system thinking to global problems.

In “Thinking in Systems” Meadows covers the three aspects of any system in detail: elements, interconnections and purpose. First, she introduces the concept of ‘stock’. A stock is the foundation of any system. Stocks are the elements of the system that you can see, feel, count or measure at any given time.

Examples of stock that Meadows mentions in the book are the water in a bathtub, books in a bookstore, the wood in a tree and money in the bank as examples of stock. If I think about my current job at Intercom, ‘customer conversations’ are the stock. In comparison, clothes were the stock (literally!) in my previous role at ASOS.

Stocks change over time through the action of a flow. Examples of flows are filling and draining, births and deaths, purchases and sales, growth and decay. A flow can be inbound and outbound. For example, the volume of wood in a forest’s trees is a stock. Its inflow is the growth of the trees. Its outflows are the natural deaths of trees and the harvest by loggers.

A stock takes time to change, because flows take time to change. If your stock is a semiconductor product changes in flows will be slower compared to the content that forms the stock of TikTok. Changes in stocks set the pace of the dynamics of systems and Meadows explains how system thinkers “see the world as a collection of stocks along with the mechanisms for regulating the levels in stocks by manipulating flows.”

Image Credit: Barry Richmond

Meadows explains about ‘stabilising loops’ and ‘reinforcing loops’. These are feedback loops that connect a number of connections from a stock, through a set of decisions, rules or actions that are dependent on the level of the stock. A stabilising or ‘balancing’ feedback loop is designed to close the gap between a desired and an actual state of stock:

Image Credit: Untools

In contrast, ‘reinforcing’ loops are found where elements of a system can reproduce themselves or grow continuously, so that the system amplifies. This amplifying effect can lead to growth or destruction.

Image Credit: Jakub Šlancar

Once we understand the different feedback loops that govern a system we can look at the factors that drive these loops, testing out potential scenarios and asking lots of ‘what if’ questions. Are the driving factors likely to pan out this way? If they did, how would the system react? What drives the driving factors?

There are two main reasons why systems can work really well. Firstly, systems are resilient. Meadows explains how resilience arises from a rich structure of many feedback loops that can work together to restore a system even after a major disturbance. Secondly, systems have the ability to learn, diversify and evolve. Systems can make their own structure more complex (you only have to think about organisations, processes or products that have become way more complex over time!).

Image Credit: Niru

Main learning point: For me, the main learning points from Thinking in Systems are in the latter parts of the book where Meadows talks about the importance of staying humble, staying a learner. To learn about how systems work, we need to learn by experimenting, by trial and error. It means making mistakes and admitting them. It also means celebrating complexity, embracing the messiness of complex systems. I often find that when I’m working through a system — consciously or subconsciously — the reality of making mistakes or having to work through complexity can feel pretty daunting. However, systems understanding provides me with some guardrails for managing complexity, understanding what’s really going on.

Related links for further learning:

1. https://untools.co/balancing-feedback-loop

2. https://uxdesign.cc/feedback-loops-everywhere-7dfc5f1a764b

3. https://www.niru.net/post/resilience-self-organization-and-hierarchy



Product at Intercom, author of "My Product Management Toolkit" and “Managing Product = Managing Tension” — see https://bit.ly/3gH2dOD.

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Product at Intercom, author of "My Product Management Toolkit" and “Managing Product = Managing Tension” — see https://bit.ly/3gH2dOD.