Information Gain

Publication Mitchell/97b: Machine Learning
Name Information Gain
Description

The Information Gain is a measure based on Entropy.

Given

  • a set E of classified examples and
  • a partition P = {E1, ..., En} of E.

The Information Gain is defined as
ig(E, P) := entropy(E) - entropy(Ei) * |Ei| / |E|
i=1,...,n

Intuitively spoken the Information Gain measures the decrease of the weighted average impurity of the partitions E1, ..., En, compared with the impurity of the complete set of examples E.

Algorithm ID3