Create a New Lower-level Decision Tree

To create a new lower-level decision tree, first diagram the different levels needed in the hierarchy and what decision variables and values are required to select the branches of the decision tree. The diagram should also indicate what treatments result at the termination points of each branch in the decision tree.

Once you have your decision tree diagrammed, use the following steps to enter it into the application:

1. Open the Decision Trees window.
2. In the Decision Trees pane of the Selection tab, right-click and select Insert. A new record is added to the table. (The decision tree set selected in the Decision Tree Sets pane does not affect the creation of a lower-level decision tree.)
3. Enter the tree name in the Decision Tree Name column.
4. Select the View/Edit tab. The application shows a single node that is the start of the decision tree.
5. Right-click the node and select Add. The system displays a dialog box so you can enter the number of nodes required.
6. Using the hierarchy you diagrammed, enter the number of nodes needed below the node you right-clicked in the dialog box and select OK. The system adds the entered number of nodes to the decision tree.
7. Repeat steps 5 and 6 to create the hierarchy you diagrammed.

Once the decision tree is created, the next step is to add the decision variables and values that govern what branches are selected.

1. Right-click a parent node and select Edit Decision Var Limits. The system displays a dialog box so you can select the desired decision variable.
2. In the left pane of the dialog box, select the desired decision variable. The system responds by configuring the right pane for entry of the values that cause each child node to be selected.
3. Configure the right pane of the dialog box to appropriately select each child node.
4. Select OK to close the dialog box.
5. Repeat steps 1 through 4 for the remaining parent nodes in the decision tree.

Now that the decision variables and values are set, the final task is to assign treatments to the termination points of each branch in the decision tree. For General decision trees, you will assign one treatment; for INCBEN decision trees, you will assign up to three candidate treatments.

To assign the first treatment, use the following steps:

1. Right-click the first termination node and select Edit Treatment. The system responds by displaying a dialog box so you can select the desired treatment.
2. In the dialog box, click the down arrow to display the list of treatments and select the desired treatment.
3. Select OK to close the dialog box. The selected treatment is shown in the termination node (alternate treatments are shown by hovering over the node).
   1. For an INCBEN decision tree only, right-click the same termination node and select Edit 1st Treatment Alternative. Repeat steps 2 and 3 to select the first alternate treatment. (This 1st Alternative Treatment is expensive than first Treatment.)
   2. For an INCBEN decision tree only, right-click the same termination node and select Edit 2nd Treatment Alternative. Repeat steps 2 and 3 to select the second alternate treatment. (This 2nd alternative Treatment is expensive than 1st Alternative Treatment.)
4. Repeat steps 1 through 3 for the remaining termination nodes of the decision tree.
5. Select the Selection tab.
6. Select to save the new information.