Reinforced Path Reasoning for Counterfactual Explainable Recommendation

TL;DR

This paper introduces CERec, a reinforcement learning-based method for generating item attribute-based counterfactual explanations that improve recommendation quality by efficiently exploring minimal item attribute changes.

Contribution

It proposes a novel adaptive path sampling and explanation policy to generate intuitive counterfactual explanations and enhance recommendation performance.

Findings

CERec provides explanations aligned with user preferences.

CERec improves recommendation accuracy and relevance.

The method effectively reduces search space for counterfactuals.

Abstract

Counterfactual explanations interpret the recommendation mechanism via exploring how minimal alterations on items or users affect the recommendation decisions. Existing counterfactual explainable approaches face huge search space and their explanations are either action-based (e.g., user click) or aspect-based (i.e., item description). We believe item attribute-based explanations are more intuitive and persuadable for users since they explain by fine-grained item demographic features (e.g., brand). Moreover, counterfactual explanation could enhance recommendations by filtering out negative items. In this work, we propose a novel Counterfactual Explainable Recommendation (CERec) to generate item attribute-based counterfactual explanations meanwhile to boost recommendation performance. Our CERec optimizes an explanation policy upon uniformly searching candidate counterfactuals within a reinforcement learning environment. We reduce the huge search space with an adaptive path sampler by using rich context information of a given knowledge graph. We also deploy the explanation policy to a recommendation model to enhance the recommendation. Extensive explainability and recommendation evaluations demonstrate CERec's ability to provide explanations consistent with user preferences and maintain improved recommendations. We release our code at https://github.com/Chrystalii/CERec.