Gain ratio Sample Clauses

Gain ratio. With the introduction of C4.5 came, among other improvements over ID3, a new criterion called gain ratio. The gain ratio criterion addresses the defi- ciency of the gain criterion expressed above, by dividing the information gain of a test by the split info of that test. The split info measure is similar to the info measure in Equation 3.1, but instead of looking at the class distribution of the subsets it only looks at the sizes of the subsets. In this way split info measures the potential of information generated by dividing a data set into several subsets. Thus split info[X|T ] = − Σ TX | | |T | × log 2 |T | i , (3.4) |T | where as above TX is the i-th subset after splitting data set T using a test