This paper introduces ICET, a new algorithm for cost-sensitive classification. ICET
uses a genetic algorithm to evolve a population of biases for a decision tree induction algorithm.
The fitness function of the genetic algorithm is the average cost of classification
when using the decision tree, including both the costs of tests (features, measurements) and
the costs of classification errors. ICET is compared here with three other algorithms for
cost-sensitive classification — EG2, CS-ID3, and IDX — and also with C4.5, which classifies
without regard to cost. The five algorithms are evaluated empirically on five realworld
medical datasets. Three sets of experiments are performed. The first set examines the
baseline performance of the five algorithms on the five datasets and establishes that ICET
performs significantly better than its competitors. The second set tests the robustness of
ICET under a variety of conditions and shows that ICET maintains its advantage. The third
set looks at ICET’s search in bias space and discovers a way to improve the search