Chapter 16: Diagrams of Casual Process

 Chapter 16: Diagrams of Casual Process

• Diagrams of Causal Processes are visual representations of the relationships and interactions between variables or factors that influence the outcome of a process. 
• These diagrams aim to capture the direction and magnitude of causal effects and can be used to identify potential confounding (surprising) variables and to plan experiments to test causality. 
• Causal processes are often complicated. Here are some diagrams that can make them easier to understand. They are also useful in giving presentations.

Casual Networks

• A casual network diagram, also known as a causal loop diagram, is a graphical representation used in systems thinking to identify and understand the relationships between variables and how changes in one variable can impact others. 
  
  
  
• It is used to analyse complex systems and helps to identify feedback loops and the potential for reinforcing or balancing forces. Casual network diagrams often use arrows to represent the direction and strength of cause-and-effect relationships between variables. They are commonly used to improve decision-making and problem-solving.
• In a causal network diagram, nodes (a point in a network or diagram at which lines or pathways intersect or branch) represent events and arrows link causes to effects. 
• We can also use annotated arrows to provide more information about the causal links. For example, a positive sign [+] next to an arrow linking A to B indicates that A increases the probability of B. A negative sign [-] indicates that A decreases the probability of B. One might even assign numerical probabilities.  
• With enough information, we can calculate the probabilities relating to other events, and predict how the system responds to changes. This is known as a Bayesian network or Bayes net.

Fishbone Diagrams

• These diagrams are also called cause and effect diagrams, and they were made popular by Kaoru Ishikawa, a Japanese professor who used them in quality management. 
  
  
  
• Such diagrams help us visualise and classify the causal factors that contribute to an effect. We start with a diagram that resembles a fish skeleton and places the problem or issue to be investigated at the fish head. We then add branches corresponding to different categories of causal factors. Specific factors under a category are then listed along the branches. The following example shows some of the main reasons why a user ends up taking a blurry photo with a camera:
  
• 
  A fishbone diagram is useful when it is possible to provide a simple classification of the different types of causes that lead to an effect. The choice of categories is crucial if the diagram is to provide an informative analysis of the overall situation. For example, if you want to improve your performance in a certain area, the relevant categories might include skill, training, environment, and personality.

Flowcharts

• A flowchart is a diagram using connected shapes to represent the steps of a complex process, some of which might involve actions and decisions. The example below describes how a busy person ruthlessly deals with the flood of emails in his inbox: 
  
  
  
• The chart says that unimportant emails are deleted. Important but non-urgent ones are set aside to be replied to later. Otherwise, a reply is sent right away. Originally, flowcharts were used in computer science to describe the different steps of a computer program. But because flowcharts are useful for describing complex procedures, they are now routinely used in many other areas as well, from customer service to medical diagnosis. Writing down a flowchart forces us to be clear about the different steps of a procedure. It can then be used as the basis of discussion, to see how a process can be improved. It can be also used as a recipe for different people to follow to ensure uniformity in how a task is to be completed. Furthermore, if more than one person is involved in completing a task, we can use a flowchart to assign people different parts of the task, so that each person knows exactly what his or her responsibilities are. 

EXERCISES

1. Suppose someone thinks that playing violent video games does not cause violent behaviour. Rather, having a violent personality causes people to play lots of these games and engage in violence. Draw a causal network diagram showing the causal processes involved.  
   
   
   
   
   
2. Consider these five steps for a pedestrian to cross the road safely, in random order: "look left and right," "stop at the curb," "walk across quickly," "wait a few seconds," "check if the road is clear”. Draw a flowchart for the whole process using only these steps.