Changing what the tree calculates - Calculation Method "Simple"

15.4 Changing what the tree calculates - Calculation Method "Simple"

The Simple Tree Preferences category for Simple Calculation is presented below, highlighting the three areas to change.

Optimal path

All calculation methods in TreeAge Pro require you to specify how decisions should be made in the tree (i.e., during roll back). This is done using the option labeled Optimal path.

The default optimal path criterion used for new trees is High, unless you save new default Preference Set. This setting would be changed if, for example, you were modeling project costs (to find the strategy with the lowest expected cost).

To set the optimal path criterion:

Select the tree and open the Tree Preferences dialog.
Select the category Simple within the Calculation Method group.
Next to the label Optimal path, select the radio buttom for either High (maximize expected values) or Low (minimize expected values).

For a tree set to High (e.g., one whose payoffs are in terms of life expectancy), at each decision node TreeAge Pro will select the alternative with the highest numeric value.

For a tree set to Low (e.g., one whose payoff formula is in terms of costs), the alternative with the lowest numeric value is selected.

Each of the payoff sets will store its own optimal path criterion for Simple calculations, and each form of multi-attribute calculations also has its own optimal path setting.

Active payoff

In TreeAge Pro, you can enter any number of payoffs at each terminal node. In a Simple analysis, you can use any one of the enabled payoff/reward sets. The Active payoff tree preference is used to select the active payoff the model should use for the Simple Calculation Method.

To change the active payoff:

In the Calculation Method "Simple" preferences, select a payoff set in the Active payoff field.
When you change to a new Active payoff for the first time in a tree, ensure that you select the appropriate optimal path criterion and numeric formatting for that payoff (options which you can find under the Calculation options in the Tree Preferences).