Attribution Explanations for Deep Neural Networks: A Theoretical Perspective

TL;DR

This paper reviews recent theoretical advances in attribution explanations for deep neural networks, addressing challenges in comparing, understanding, and evaluating the faithfulness of attribution methods.

Contribution

It offers a comprehensive summary of theoretical unification, rationale, and evaluation approaches, providing insights for better method selection and development.

Findings

Unification of attribution methods enables systematic comparison.

Theoretical foundations clarify the rationale behind existing methods.

Rigorous evaluation frameworks assess faithfulness of attribution methods.

Abstract

Attribution explanation is a typical approach for explaining deep neural networks (DNNs), inferring an importance or contribution score for each input variable to the final output. In recent years, numerous attribution methods have been developed to explain DNNs. However, a persistent concern remains unresolved, i.e., whether and which attribution methods faithfully reflect the actual contribution of input variables to the decision-making process. The faithfulness issue undermines the reliability and practical utility of attribution explanations. We argue that these concerns stem from three core challenges. First, difficulties arise in comparing attribution methods due to their unstructured heterogeneity, differences in heuristics, formulations, and implementations that lack a unified organization. Second, most methods lack solid theoretical underpinnings, with their rationales remaining absent, ambiguous, or unverified. Third, empirically evaluating faithfulness is challenging without ground truth. Recent theoretical advances provide a promising way to tackle these challenges, attracting increasing attention. We summarize these developments, with emphasis on three key directions: (i) Theoretical unification, which uncovers commonalities and differences among methods, enabling systematic comparisons; (ii) Theoretical rationale, clarifying the foundations of existing methods; (iii) Theoretical evaluation, rigorously proving whether methods satisfy faithfulness principles. Beyond a comprehensive review, we provide insights into how these studies help deepen theoretical understanding, inform method selection, and inspire new attribution methods. We conclude with a discussion of promising open problems for further work.