Geodesic Expert Routing for Unbiased Knowledge Distillation in Recommendation
Geodesic Expert Routing for Unbiased Knowledge Distillation in Recommendation
Xuan Zhang, Rongchuan Wei, Chunyu Wei, Hongxing Yuan, Yushun Fan
Proceedings of the Thirty-Fifth International Joint Conference on Artificial Intelligence
Main Track. Pages 3250-3258.
https://doi.org/10.24963/ijcai.2026/361
Knowledge distillation has become a prevalent technique for deploying efficient recommender systems, enabling lightweight student models to approximate the performance of larger teachers. However, we identify a critical issue: distillation systematically amplifies popularity bias, as student models inherit and intensify the popularity-driven shortcuts encoded in teachers trained on interaction data dominated by popular items. To address this limitation, we propose GUIDE (Geodesic aware Unbiased Instructive Distillation with Experts), a collaborative distillation framework that incorporates domain-specific debiasing experts alongside the global teacher. GUIDE tackles two key challenges in this paradigm. First, for expert routing, we introduce Spherical Expert Alignment, which conducts expert-student matching on the spherical manifold with geodesic distance optimization, eliminating magnitude-induced bias and ensuring stable gradient flow. Second, for context fusion, we design a Meta-Debiasing Gate that dynamically arbitrates teacher-expert influence based on real-time user-item context through end-to-end meta-learning. Extensive experiments on multiple real-world datasets demonstrate that GUIDE significantly mitigates popularity bias while preserving recommendation accuracy, with state-of-the-art trade-offs among efficiency, accuracy, and fairness. The code and data are available at:https://github.29com/zx19971219/GUIDE.
Keywords:
Data Mining: Recommender systems
Machine Learning: Deep learning architectures
