Distribution-Based Feature Attribution for Explaining the Predictions of Any Classifier

The proliferation of complex, black-box AI models has intensified the need for techniques that can explain their decisions. Feature attribution methods have become a popular solution for providing post-hoc explanations, yet the field has historically lacked a formal problem definition. This paper addresses this gap by introducing a formal definition for the problem of feature attribution, which stipulates that explanations be supported by the given dataset representing an underlying probability distribution. Our analysis reveals that many existing model-agnostic methods fail to meet this criterion, while even those that do often possess other limitations. To overcome these challenges, we propose Distributional Feature Attribution eXplanations (DFAX), a novel, model-agnostic method for feature attribution. DFAX is the first to explain classifier predictions from a distributional perspective. We show through extensive experiments that DFAX is more effective and efficient than state-of-the-art baselines.