Comparative Explanations via Counterfactual Reasoning in Recommendations
Yi Yu, Zhenxing Hu
TL;DR
This work tackles the fidelity of explanations in recommender systems by moving from reduction-based counterfactuals to a comparative counterfactual framework. CoCountER leverages differentiable swap operations on item aspects to generate counterfactual explanations for arbitrary item pairs, identifying the most influential aspects that flip ranking under a black-box predictor. Empirical results across three Amazon domains show that CoCountER consistently improves the Probability of Necessity and Probability of Sufficiency over baselines like CountER, demonstrating more faithful, context-aware explanations. The approach offers a practical pathway to more trustworthy explanations and suggests future integration with generative models to produce natural language counterfactuals.
Abstract
Explainable recommendation through counterfactual reasoning seeks to identify the influential aspects of items in recommendations, which can then be used as explanations. However, state-of-the-art approaches, which aim to minimize changes in product aspects while reversing their recommended decisions according to an aggregated decision boundary score, often lead to factual inaccuracies in explanations. To solve this problem, in this work we propose a novel method of Comparative Counterfactual Explanations for Recommendation (CoCountER). CoCountER creates counterfactual data based on soft swap operations, enabling explanations for recommendations of arbitrary pairs of comparative items. Empirical experiments validate the effectiveness of our approach.
