1) Create a stock/level accumulation

2) Add a flow/rate
 

Constant rate

Constant rate with connectors

Rate with feedback

Rate with feedback and policy variable

3) Add an outflow
 

Simple

With connectors and simple function

Would there be any difference in the tabular output of the people stock in the following stock and flow diagrams A,B?
 

A. 

B. 

* Note: the symbols and equation design contained in this document were created using ithink_TM from High Performing Systems.
(c) 1999 John H. Saunders