"In consulting, I usually start with causal loop diagrams before going on to stock and flows. The exception is when I see immediately a very clear and important stock and flow structure (the iThink folks might call this a "main chain") in which case, I might dive into the stock and flow right from the start."In teaching the SD applications course here at MIT, we encourage students to start with causal loop diagrams. One reason for this is that students who start with stocks and flows often never complete any important feedback loops.
"Other reasons to start with causal loop diagrams include:
- CLD's are usually more dramatic and hence capture the interest of students and clients alike (its good to start with a bang).
- Causal loop diagrams lead to insights on their own more frequently than stock and flow diagrams do. (Note, I am distinguishing between stock and flow diagrams and the simulation model).
- Causal loops are easy to develop at a relatively high level of abstraction - this means that they can provide an overview of the system you are modeling, before getting down to the nitty gritty.
- Causal loop diagrams are fuzzier, so they can be drawn even if you are not yet clear on every single concept (this is a common state at the beginning of the project).
- Causal loop diagrams are cheap relative to simulation modeling (and cheap relative to an equation-level stock and flow diagram). This means you can more quickly get a comprehensive feel for the problem area. And inexpensively generate some initial insights."