Getting Started with the Influence Diagram
An influence diagram is a graphical representation of a problem. It is a very powerful brainstorming tool. Using just 5 elements, you can depict the key elements of the decision context. They are:
|A 'decision' is a variable that represents 'what you can do'.|
|A 'chance' is a variable that represents 'what you cannot do' or what can be uncertain outcomes, that you do not have control.|
|An 'objective' is a variable that represents 'a matter that you care about'. For example, it can be "Net Profit" in an investment decision.|
|A 'deterministic' is a variable that represents, 'what can be determined from other variables'. So, it is a calculated value, a value that is derived from other variables.|
|An 'influence' means a variable can change the state of another variable. It is represented by an arrow connecting 2 elements. For example, an uncertain outcome can depend on what action you take. An uncertain outcome can affect your net utility value (objective). So, an arrow can be connected from that uncertain chance element to your objective element.|
In the Influence Diagram Canvas application, these elements are available to drag and drop on the canvas.
So, once you have a decision problem in mind that you want to jot down, simply drag and drop a decision element to the canvas. Draw a connector from one element to another as shown below:
Double click on any node to edit the text on the node.
Once you connect to a node using an arrow, you can double click on the arrow to annotate the arrow.
Whenever you need more space, simply click the expand button as shown below:
Once your diagram grows big, you can use pan and zoom feature to navigate around the parts.
So, basically, there is nothing complicated about this tool. A typical influence diagram looks like this:
Once you are done drawing the diagram, you can save the project form the file menu. Also, you can export the diagram as an image from the file menu.