CARD: Cluster-level Adaptation with Reward-guided Decoding for Personalized Text Generation

Yutong Song, Jiang Wu, Weijia Zhang, Chengze Shen, Shaofan Yuan, Weitao Lu, Jian Wang, Yu Wang, Nikil Dutt, Amir M. Rahmani


Abstract
Adapting large language models to individual users remains challenging because systems must capture fine-grained personal preferences while serving many users efficiently. We introduce CARD, a hierarchical personalization framework that first learns preferences shared across user groups and then captures how individual users depart from those shared patterns. CARD trains a parameter-efficient adaptation module for each group, providing a reliable prior even when a user has limited history. It then learns a compact user preference vector by contrasting user-authored responses with outputs from the corresponding group model, without requiring manual annotations. During inference, both the backbone and the group adaptation module remain frozen, while the user vector applies a low-rank correction to the token logits during decoding. Experiments on personalization benchmarks show that CARD consistently outperforms competitive baselines while requiring only a compact vector for each user.
Anthology ID:
2026.findings-emnlp.44
Volume:
Findings of the Association for Computational Linguistics: EMNLP 2026
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
Findings
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
889–908
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URL:
https://aclanthology.org/2026.findings-emnlp.44/
DOI:
Bibkey:
Cite (ACL):
Yutong Song, Jiang Wu, Weijia Zhang, Chengze Shen, Shaofan Yuan, Weitao Lu, Jian Wang, Yu Wang, Nikil Dutt, and Amir M. Rahmani. 2026. CARD: Cluster-level Adaptation with Reward-guided Decoding for Personalized Text Generation. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 889–908, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
CARD: Cluster-level Adaptation with Reward-guided Decoding for Personalized Text Generation (Song et al., Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-emnlp.44.pdf