Distilling LLM Reasoning into Dense Encoders: Bridging the Accuracy-Efficiency Gap in Recommendation

Donghee Han, Daeyoung Roh, A Young Kim, Hwanjun Song, Mun Yong Yi


Abstract
Large Language Models (LLMs) have shown remarkable potential in recommendation systems but suffer from prohibitive inference latency. Existing distillation approaches typically target Small Language Models (SLMs) or Conventional Recommendation Models (CRMs), face a critical trade-off between computational cost and semantic reasoning capacity. To bridge this accuracy-efficiency gap, we introduce Reasoning-to-Encoder Distillation (R2END), a framework that establishes a text encoder as the optimal student architecture for scalable recommendation. Unlike methods that mimic token generation, R2END compresses the teacher’s reasoning into a dense vector space via a semantic alignment objective, effectively capturing user-item dynamics. Extensive experiments on four datasets demonstrate that R2END not only outperforms state-of-the-art baselines but also achieves drastically reduced latency, offering a sweet spot for recommendation.
Anthology ID:
2026.findings-acl.1130
Volume:
Findings of the Association for Computational Linguistics: ACL 2026
Month:
July
Year:
2026
Address:
San Diego, California, United States
Editors:
Maria Liakata, Viviane P. Moreira, Jiajun Zhang, David Jurgens
Venue:
Findings
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Publisher:
Association for Computational Linguistics
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Pages:
22513–22531
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URL:
https://preview.aclanthology.org/ingest-acl/2026.findings-acl.1130/
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Cite (ACL):
Donghee Han, Daeyoung Roh, A Young Kim, Hwanjun Song, and Mun Yong Yi. 2026. Distilling LLM Reasoning into Dense Encoders: Bridging the Accuracy-Efficiency Gap in Recommendation. In Findings of the Association for Computational Linguistics: ACL 2026, pages 22513–22531, San Diego, California, United States. Association for Computational Linguistics.
Cite (Informal):
Distilling LLM Reasoning into Dense Encoders: Bridging the Accuracy-Efficiency Gap in Recommendation (Han et al., Findings 2026)
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https://preview.aclanthology.org/ingest-acl/2026.findings-acl.1130.pdf
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