MAPPING ‘CAUSE’ AND ‘EFFECT’ REINFORCING AND BALANCING RELATIONSHIPS ON VENSIM
STEP 1
Download the Vensim software which can be downloaded for educational purposes for free from the following link: Free Downloads | Vensim
STEP 2
Draw ‘cause’ and ‘effect’ relationships as below. A detailed tutorial on how to do this can be found at the following You Tube video:
If we go back to the previous example, we will draw the relationships as below.
- Open a ‘New Model’ from ‘File
b. Draw the first variable ‘connection of the market with the High Street’ (cause) by clicking on the symbol ‘A’. If you right click on the variable you have the option to include in shapes, or use different colours.
c. Draw the second variable (effect) i.e. Market growth
d. Draw the relationship by clicking on the ‘arrow’ button
e. Right click on the arrow to select the symbol of (+) or (-) depending on the relationship. In this case the symbol is (+) as the relationship is reinforcing. The ‘more’ the market connects with the High Street, the ‘more’ the market grows.
f. Now consider if this relationship returns back to the cause. In other words, consider if the ‘effect’ (market growth) is also a ‘cause’ for reinforcing the ‘connection of the market with the High Street’. In this case it is a logical assumption to make. Hence, we can create a reinforcing loop by clicking on the arrow that connects the ‘market growth’ with the ‘connection of the market with the High Street’.
g. We can insert a little label within the loop which might be of help later for communication purposes since our system will be growing consisting of many non-linear loops. To do this, we click on the ‘comment tool’ which has the image of a ‘comment’. A dialog box will open where we can type the type of relationship. This can the letter R for reinforcing or B for balancing relationship. A short description can be added that qualifies the relationship.