Nested Logit model: Edit decision tree

1.  Make sure of the following:

• in the procedure sequence, the Tour-based model - Combined trip distribution / mode choice procedure has been created (Calculating tour-based model - combined trip distribution and mode choice)
• The Parameters: Tour-based model - Combined trip distribution / mode choice window is open.

2.  Select the Mode choice utility tab.

3.  Choose the option Use nested logit model for mode choice.

4.  Click the Decision tree button.

A query might open. Click Yes to confirm the query, to apply the utility definition and the scaling factor of person groups / destination activity / mode with Logit function type in the Nested Logit model. The Edit decision tree window opens and the existing root nodes for the decision tree are displayed.

5.  Make the desired settings.

Element	Description
Create nested node	The Create nested node window opens, in which you can create nest nodes underneath the root node (Create nested node).
Create mode node	The Create mode node window opens, in which you can allocate a new mode node to a nest node (Create mode node).
Edit marked nest/mode node.	Opens the Edit nest/mode node window (Edit nest or mode node)
Delete marked nest/mode node.	Deletes a marked nest or mode node. Note You cannot delete the root node. For each mode, there must be at least one mode node in the decision tree, so that you cannot delete the last mode node of an existing mode.

Create nested node

You can create additional nested nodes underneath each nested node. The number of levels is not restricted by Visum. If, however, you would like to use the Cross Nested Logit model for which a mode is allocated to a number of nest nodes, you should not nest the nest nodes (Fundamentals: Calculating tour-based model - combined trip distribution and mode choice).

1.  Make sure that the Edit decision tree window is open.

2.  Click the  Create nested node icon.

3.  Make the desired changes

Element	Description
Parent node	Selection of the parent node under which the new nest node is created
Name of the node	Unique name of the nest node

4.  Confirm with OK.

Create mode node

1.  Make sure that the Edit decision tree window is open.

2.  Click the  Insert mode node icon.

3.  Make the desired changes

Element	Description
Parent node	Selection of the parent node under which the new nest node is created
Mode name	Selection of the mode for the mode node

Edit nest or mode node

1.  Make sure that the Edit decision tree window is open.

2.  Click the Edit marked nest/mode node icon.

3.  Make the desired changes.

Element	Description
Edit nested node	Parent node selection list Selection of the parent node under which the nest node is created Name of the nest Renaming the network node
Edit mode node	Parent node selection list Selection of the parent node under which the mode node is created