Overview: Causal Loop Diagrams (CLDs)

A useful way to explain or communicate your model is to present it, or a simplification of it, as a causal loop diagram (CLD). A CLD lets you show only the dominant feedback loops or selected causal connections between variables in your model.

By using a CLD, other people can quickly see the overall causal relationships in the model without being distracted by the other details that are necessary to simulate the model. There are two approaches to creating causal loop diagrams.

Conceptual CLDs are used to communicate feedback loops. They're created as standalone maps that use the same names as a simulating model, but don't include all of the detail or any of the stock and flow structure. Consider the following example:

Here we use B to denote a balancing loop and R to denote a reinforcing loop. To learn how to build conceptual CLDs, see Creating CLDs.

Module Maps are a form of causal loop diagrams at the module level. These indicate how different modules interact and can be useful for providing an overview of a relatively complex model. These diagrams can (and should) be built with working simulation models, and are kept consistent with the actual model by the software. Consider the following example:

For more information on building module maps, which are a natural result of organizing your model into modules, see Working with Modules.