The Effect of Balancing Methods on Model Behavior in Imbalanced
  Classification Problems
Adrian Stando Mustafa Cavus Przemysław Biecek
Imbalanced data poses a significant challenge in classification as model
performance is affected by insufficient learning from minority classes.
Balancing methods are often used to address this problem. However, such
techniques can lead to problems such as overfitting or loss of information.
This study addresses a more challenging aspect of balancing methods - their
impact on model behavior. To capture these changes, Explainable Artificial
Intelligence tools are used to compare models trained on datasets before and
after balancing. In addition to the variable importance method, this study uses
the partial dependence profile and accumulated local effects techniques. Real
and simulated datasets are tested, and an open-source Python package edgaro is
developed to facilitate this analysis. The results obtained show significant
changes in model behavior due to balancing methods, which can lead to biased
models toward a balanced distribution. These findings confirm that balancing
analysis should go beyond model performance comparisons to achieve higher
reliability of machine learning models. Therefore, we propose a new method
performance gain plot for informed data balancing strategy to make an optimal
selection of balancing method by analyzing the measure of change in model
behavior versus performance gain.