To use the Decision
Tree node to interactively train and prune a decision tree:
-
From the
Model tab
on the Toolbar, select the
Decision Tree node
icon. Drag the node into the Diagram Workspace.
-
In the Diagram Workspace,
right-click the
Decision Tree node, and select
Rename from
the resulting menu. Enter
Interactive Decision
Tree
and then click
OK in
the window that opens.
-
Connect the Control
Point node to the Interactive Decision Tree node.
-
Select the
Interactive
Decision Tree node. In the Properties Panel, in the
Train properties
group, click on the ellipses that represent the value of
Interactive.
The
Interactive Decision Tree window appears.
-
Select the root node
(at this point, the only node in the tree), and then from the
Action menu,
select
Split Node. The
Split Node window
appears that lists the candidate splitting rules ranked by logworth
(-Log(p)). The FREQUENCY_STATUS_97NK rule has the highest logworth.
Ensure that this row is selected, and click
OK.
-
The tree now has two
additional nodes. Select the lower left node (where FREQUENCY_STATUS_97NK
is 3 or 4), and then from the
Action menu,
select
Split Node. In the
Split
Node window that opens, select MONTHS_SINCE_LAST_GIFT,
which ranks second in logworth, and click
Edit Rule to
manually specify the split point for this rule. The
Interval
Split Rule window appears.
Enter
8
as
the
New split point, and click
Add
Branch. Then, select Branch 3 (>= 8.5) and click
Remove
Branch. Click
OK.
Ensure that MONTHS_SINCE_LAST_GIFT
is selected in the
Split Node window, and
click
OK.
-
Select the first generation
node that you have not yet split (where FREQUENCY_STATUS_97NK is 1,
2, or Missing). From the
Action menu, select
Split
Node. In the
Split Node window
that opens, ensure that PEP_STAR is selected, and click
OK.
The tree now has seven
nodes, four of which are leaf nodes. The nodes are colored from light
to dark, corresponding to low to high percentages of correctly classified
observations.
-
Select the lower right
node (where FREQUENCY_STATUS_97NK is 1, 2, or Missing and PEP_STAR
is 0 or Missing). From the
Action menu, select
Train
Node. This selection causes SAS Enterprise Miner to continue
adding generations of this node until a stopping criterion is met.
For more information about stopping criteria for decision trees, see
the SAS Enterprise Miner Help.
Note: In the
Interactive
Decision Tree window, you can prune decision trees. However,
in this example, you will leave the tree in its current state.
-
Close the
Interactive
Decision Tree window.