System Design

Week 4 Recording

Systems change by their very nature, and understanding this change over time is a fundamental aspect of systems thinking and systems analysis. 

You will have many personal experiences of thing changing over time and for the organisation you are studying, you could collect a range of data from aspects that change over time and represent this data using graphs, infographics, and in databases. 

System involve:  

• aspects that change over time;  

• how these changed over time;  

• the period the change occurred; and 

•  if the change is constant, increasing, decreasing or fluctuating. 

Once graphed many of these aspects will become obvious, and you can consider what may have caused any changes in direction or slope, you can also consider what may happen in the future – extrapolating the change and developing trends. If several things to do with organisation are changing, they can be explored by examining the relationships between different graphs - the interdependencies or causal relationships.

Stocks are the foundation of any system - they are what you can see, feel, count or measure - but they do not have to be physical. In system models, stocks can be things such as water in reservoirs or a bathtub, money, air quality, animal populations, human populations, but can also include immaterial things such as confidence, fear, patience or hope - as long as they can be measured and change. 

Change can result in stocks increasing, decreasing, or oscillating up and down. 

Change in stock over time is through the action of a flow within a system, for example in a bathtub, we have an inflow through a faucet, and an outflow through a drain. If the flow in is greater than the flow out, the stock will increase, if less, then the stock of water in the tub will decrease. 

Stock and flow can be used to understand many systems, including those in stories, poltics, and in our case, educational organisations. 

Flow models are used to represent and better understand what is occurring over time. 

Stock and flow models can be used to identify the loops formed when changes in stock change the flow in and out of that same stock, and do so in two forms:  

• Balancing: in which a feedback loop acts to try and keep a stock within a certain range; and  

• Reinforcing: where the stock can increase or decrease exponentially. 

Simple Feedback loops can be seen in many real world problems. World population, avalanches, Epidemics, rumours, fads, interest rates, confidence, soil fertility, predator-prey systems, exercise, supply and demand, fire management, and cruise control.

Feedback loops can be connected together and interact. 

There are two types of feedback loops: balancing and reinforcing. 

A loop can be identified as reinforcing or balancing by counting the number of negative connections, if it is an odd number - it will be a balancing loop, otherwise a reinforcing loop. 

Stock flow diagrams can become quite complex, and involve many loops. Connection circle are an alternative way of identifying feedback loops. 

• Stock flow maps are the most involved, and provide detailed understanding of the changes involved. 

• Connection circles can be created much quicker, but may only provide a basic understanding. 

As we explored last week, connection circles are formed by identifying and placing around the circumference, all of the elements involved in a system. Then arrowed lines are drawn showing how elements affect one another, with + and - labels for positive and negative effects. From this, loops can be identified, and feedback or causal loops generated. 

Using these two techniques, stock flow maps, and connection circles, you should be able to quickly generate causal feedback loops to better understand the system that you are exploring. Feedback loops allow you to identify those aspects of the system that can be improved or changed by the use of an educational technology or key actors within your system that you will need to influence to ensure the success of your transformation plan.