Creating nodes

A DynRisk model consists of two kinds of objects: “nodes” and “edges”. The nodes represent the variables in the model, while the edges represent dependencies between these variables. The graphical structure obtained when the nodes and edges are linked together, is called an “influence diagram”.

We will start by creating the “goal node” of the model: the “Revenue” node. In DynRisk there are five different menu items you can use to create new nodes. All items are located in a hierarchical menu found under “New node” in the “Model” menu. These items correspond to five different node types: “Independent”, “Sum”, “Product”, “Maximum” and “Minimum”. You will learn more about these later. For now, just think of the node type as a description of what the node does with input from other nodes. Thus, e.g., a sum node adds up all its input, an independent node ignores input etc.

Since we want the “Revenue” node to add up things, you select “New node->Sum” from the “Model” menu. Alternatively, you can click the “Sum” button in the toolbar.

As a result you should get a new object in the window.

[When it is created, it is automatically hilited, indicating that it is “selected”. Click somewhere else in the window to deselect it.]