Credit Risk Assessment with Stacked Machine Learning
摘要
This study compares S-ICAS with advanced machine learning (ML) techniques, including random forests, extreme gradient boosting, deep learning, and a stacked ensemble that integrates their predictions. Using a dataset of over 2.5 million firm-year observations from 2014 to 2023, we assess whether these methods improve discriminatory power relative to S-ICAS. Results show that tree-based ensembles outperform the financial and behavioural components of S-ICAS, while deep learning contributes additional information when combined within the stacked model. The meta-model consistently delivers higher predictive accuracy, particularly during periods of economic disruption, such as the Covid-19 crisis, indicating greater robustness than S-ICAS. However, interpretability challenges limit the stand-alone use of ML in regulatory contexts. To address this, we employ eXplainable Artificial Intelligence (XAI) tools, specifically Shapley values, to identify the drivers of discrepancies between ML and S-ICAS outputs. This enhances analysts’ ability to refine second-stage assessments and ensures transparency. Overall, our findings suggest that ML and XAI can complement, but not replace, traditional models, improving both the effectiveness and resilience of the ICAS process.