Demystifying Sequential Recommendations: Counterfactual Explanations via Genetic Algorithms

TL;DR

This paper introduces a novel counterfactual explanation method for Sequential Recommender Systems using a specialized genetic algorithm, addressing the challenge of interpretability in complex sequential models.

Contribution

It presents the first counterfactual explanation technique tailored for SRSs, demonstrating its effectiveness across multiple datasets and models.

Findings

Successfully generates interpretable counterfactual explanations

Maintains high model fidelity close to one

Applicable across various datasets and models

Abstract

Sequential Recommender Systems (SRSs) have demonstrated remarkable effectiveness in capturing users' evolving preferences. However, their inherent complexity as "black box" models poses significant challenges for explainability. This work presents the first counterfactual explanation technique specifically developed for SRSs, introducing a novel approach in this space, addressing the key question: What minimal changes in a user's interaction history would lead to different recommendations? To achieve this, we introduce a specialized genetic algorithm tailored for discrete sequences and show that generating counterfactual explanations for sequential data is an NP-Complete problem. We evaluate these approaches across four experimental settings, varying between targeted-untargeted and categorized-uncategorized scenarios, to comprehensively assess their capability in generating meaningful explanations. Using three different datasets and three models, we are able to demonstrate that our methods successfully generate interpretable counterfactual explanation while maintaining model fidelity close to one. Our findings contribute to the growing field of Explainable AI by providing a framework for understanding sequential recommendation decisions through the lens of "what-if" scenarios, ultimately enhancing user trust and system transparency.