This is a topic I know little about. I know just enough to recognize the importance of what I learned.
The story goes that a supplier of a range of packaging inquired with his clients why orders for a particular product's packaging slowed down.
His clients responded that this product's sales went down by 30%, not 3%, not 13%, but 30%. He was curious and asked if they knew what drove this change, they responded in the negative. They had no idea why, and were stumped as to the cause.
So this supplier started investigating the situation, and he learned that there was an increase in the number of families choosing to repatriate their to their home countries after the school year ended.
A tax had been levied on families. This simple act that was meant to increase the city coffers resulted in the absence of the children who purchased this product daily. This is why there was a 30% decline in product orders.
I'm reminded of the book by Donella Meadows, Thinking in Systems. Where she clarifies how easy it is to ignore interconnections at our own peril.