Decision Tree

Structure of a Decision Tree

Decision trees have three main parts: a root node, leaf nodes and branches. The root node is the starting point of the tree, and both root and leaf nodes contain questions or criteria to be answered. Branches are arrows connecting nodes, showing the flow from question to answer. Each node typically has two or more nodes extending from it. For example, if the question in the first node requires a "yes" or "no" answer, there will be one leaf node for a "yes" response, and another node for "no."

How to Make a Decision Tree Automatically from Data

You can also create a decision tree automatically using data. All you have to do is format your data in a way that SmartDraw can read the hierarchical relationships between decisions and you won't have to do any manual drawing.

Learn more about generating decision trees from data.

Seven Tips for Creating a Decision Tree

Here are some best practice tips for creating a decision tree diagram:

• Start the tree. Draw a rectangle near the left edge of the page to represent the first node. In this rectangle, write the first question, main idea, or criterion that will lead to a decision.
• Add branches. For every possible alternative draw a separate line that begins at the node and moves away toward the right of the page. Using a loan approval process as an example, the first node may have been "Income", and the associated branches might be <$50K, $51K - $100K, >$101K.
• Add leaves. The bulk of the decision tree will be leaf nodes. At the end of each branch add a leaf node. Fill each of these leaf nodes with another question or criterion.
• Add more branches. Repeat the process of adding a branch for each possible alternative leading from a leaf. Label each branch just as before.
• Complete the decision tree. Continue adding leaves and branches until every question or criterion has been resolved and an outcome has been reached.
• Terminate a branch. Continue adding leaves and branches until every question or criterion has been resolved and an outcome has been reached.
• Verify accuracy. Consult with all stakeholders to verify accuracy.