Introduction

Decision Trees are a fundamental algorithm in machine learning used for both classification and regression tasks. 🧠 They work by splitting data into subsets based on feature values, creating a tree-like structure where each internal node represents a decision, and each leaf node represents an outcome.

decision tree structure

Figure: Basic structure of a decision tree

How It Works

  1. Root Node: Start with the entire dataset.
  2. Splitting: Select the best feature to split the data (e.g., using Gini impurity or information gain).
  3. Recursive Partitioning: Repeat the process on each subset until all data points are classified or a stopping criterion is met.
  4. Leaf Nodes: Final decisions are made at the leaves.

decision tree splitting

Figure: Splitting data based on feature values

Applications

  • Customer Segmentation 🎯
  • Medical Diagnosis 🩺
  • Predictive Analytics 📊
  • Game Theory 🎮

customer segmentation

Figure: Decision trees in customer segmentation

Advantages and Disadvantages

Advantages:

  • Easy to understand and interpret.
  • Requires little data preprocessing.
  • Handles both numerical and categorical data.

Disadvantages:

  • Prone to overfitting.
  • Not suitable for large datasets.
  • Sensitive to small changes in data.

Further Reading

For deeper insights, explore our machine learning overview or decision trees example. 📘