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Better trees: an empirical study on hyperparameter tuning of classification decision tree induction algorithms

Mantovani, Rafael Gomes; Horváth, Tomáš; Rossi, André L. D.; Cerri, Ricardo; Barbon Junior, Sylvio; Vanschoren, Joaquin; de Carvalho, André C. P. L. F.

Authors

Rafael Gomes Mantovani

Tomáš Horváth

André L. D. Rossi

Ricardo Cerri

Sylvio Barbon Junior

Joaquin Vanschoren

André C. P. L. F. de Carvalho



Abstract

Machine learning algorithms often contain many hyperparameters whose values affect the predictive performance of the induced models in intricate ways. Due to the high number of possibilities for these hyperparameter configurations and their complex interactions, it is common to use optimization techniques to find settings that lead to high predictive performance. However, insights into efficiently exploring this vast space of configurations and dealing with the trade-off between predictive and runtime performance remain challenging. Furthermore, there are cases where the default hyperparameters fit the suitable configuration. Additionally, for many reasons, including model validation and attendance to new legislation, there is an increasing interest in interpretable models, such as those created by the decision tree (DT) induction algorithms. This paper provides a comprehensive approach for investigating the effects of hyperparameter tuning for the two DT induction algorithms most often used, CART and C4.5. DT induction algorithms present high predictive performance and interpretable classification models, though many hyperparameters need to be adjusted. Experiments were carried out with different tuning strategies to induce models and to evaluate hyperparameters’ relevance using 94 classification datasets from OpenML. The experimental results point out that different hyperparameter profiles for the tuning of each algorithm provide statistically significant improvements in most of the datasets for CART, but only in one-third for C4.5. Although different algorithms may present different tuning scenarios, the tuning techniques generally required few evaluations to find accurate solutions. Furthermore, the best technique for all the algorithms was the Irace. Finally, we found out that tuning a specific small subset of hyperparameters is a good alternative for achieving optimal predictive performance.

Journal Article Type Article
Acceptance Date Jan 1, 2024
Online Publication Date Jan 31, 2024
Publication Date 2024
Deposit Date Mar 27, 2024
Print ISSN 1384-5810
Electronic ISSN 1573-756X
Publisher Springer
Peer Reviewed Peer Reviewed
Volume 38
Pages 1364–1416
DOI https://doi.org/10.1007/s10618-024-01002-5
Keywords Decision tree induction algorithms, Hyperparameter tuning, Hyperparameter profile, J48, CART
Public URL http://researchrepository.napier.ac.uk/Output/3577299