Causal Loop Diagrams
to understand what part of the system to engage in to initiate change
to understand what part of the system to engage in to initiate change
“When you are confronted by any complex social system, such as an urban center or a hamster, with things about it that you’re dissatisfied with and anxious to fix, you cannot just step in and set about fixing with much hope of helping… You cannot meddle with one part of a complex system from the outside without the almost certain risk of setting off disastrous events that you hadn’t counted on in other, remote parts. If you want to fix something you are first obligated to understand… the whole system… Intervening is a way of causing trouble” - On Meddling (1974, Lewis Thomas)
WHAT IS A CAUSAL LOOP DIAGRAM?
A Causal Loop Diagram (CLD) is:
Example of a Causal Loop Diagram
WHAT MAKES A CAUSAL LOOP DIAGRAM A "SYSTEMS" TOOL?
WHEN MIGHT I WANT TO USE A CAUSAL LOOP DIAGRAM?
When you want to model a dynamic system in a holistic manner.
When data are not available to provide a precise characterization of a complex system.
WHAT ELSE SHOULD I KNOW ABOUT CAUSAL LOOP DIAGRAMS?
If and when data are available, CLDs can be transformed into stock and flow diagrams, in which each variable is represented by an appropriate mathematical equation, and various changes in variables of interest can be simulated to see the net effects in a system.