Gain Ratio In Decision Tree

Table Of Contents:

  1. What Is Gain Ratio In Decision Tree?
  2. Example Of Gain Ratio
  3. Interpreting Split Information

  4. What Is The Range Of Gain Ratio?
  5. What We Want ?

  6. Balanced, Unbalanced & Moderate Split

  7. Which Split Information Is Better: Balanced, Unbalanced & Moderate Split

  8. How Gain Ratio Penalized Lower Split Information?

  9. Advantages Of Gain Ratio

  10. Disadvantages Of Gain Ratio

(1) What Is Gain Ratio In Decision Tree?

  • In decision tree learning, the Gain Ratio is an improvement over Information Gain to evaluate splits.
  • While Information Gain measures the effectiveness of a feature in classifying the data, it tends to favor features with many distinct values (like a unique identifier).
  • The Gain Ratio is introduced to overcome this bias.

(2) Example Of Gain Ratio

(3) Interpreting Split Information

  • Split Information measures how “uniformly” the data is distributed across the subsets.
  • Split Information is a key component of the Gain Ratio in decision trees.
  • Its purpose is to measure how the data is divided among the branches resulting from a split.
  • Understanding its impact requires exploring its relationship with Information Gain and the decision tree’s splitting process.

(4) What Is The Range Of Gain Ratio?

  • The range of Gain Ratio is 0 to 1. Here’s why:

(5) What We Want ?

  • Achieving higher Information Gain (IG) and higher Split Information (SI) simultaneously is possible when a split divides the data both meaningfully and evenly in terms of target variable purity and subset size. Here’s how:

(6) Balanced, Unbalanced & Moderate Split

(7) Which Split Information Is Better: Balanced, Unbalanced & Moderate Split

(8) How Gain Ratio Penalized Lower Split Information?

(9) Gain Ratio Of An ID Attribute Having 10 Values.

  • The ID attribute is a unique identifier, meaning each record has a unique value.
  • When splitting on this attribute, each subset will contain exactly one record. This leads to the following characteristics:

(10) Advantages Of Gain Ratio

(11) Disadvantages Of Gain Ratio

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