LLM Feedback for Topic Model with Preference Optimization and Contrastive Learning

Tung Nguyen, Dat Phan Trong, Linh Ngo Van, Duc Anh Nguyen, Dinh Thai Hoang, Diep Nguyen


Abstract
The integration of large language models (LLMs) into topic modeling has shown promise for improving topic interpretability and coherence, particularly by exploiting the generative capabilities of LLMs through instruction-based prompting. However, existing methods often incur substantial computational cost and inference complexity. To address these limitations, we propose **LLMFeed**, a novel framework that leverages **feed**back from an **LLM** to improve topic model optimization. Specifically, the LLM is used to **evaluate** topic quality, **identify** semantic meaning, and **recommend** representative topic words. These signals are then incorporated to (i) refine topic representations via Direct Preference Optimization (DPO), and (ii) guide contrastive learning for improved document-topic assignments. Extensive experiments show that **LLMFeed** achieves a 7.6% gain in topic coherence and over 10% improvement in doc-topic distributions on 20 Newsgroups dataset, while requiring only minutes to run, compared with hours for recent LLM-integrated topic modeling methods.
Anthology ID:
2026.emnlp-main.265
Volume:
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
EMNLP
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
6021–6045
Language:
URL:
https://aclanthology.org/2026.emnlp-main.265/
DOI:
Bibkey:
Cite (ACL):
Tung Nguyen, Dat Phan Trong, Linh Ngo Van, Duc Anh Nguyen, Dinh Thai Hoang, and Diep Nguyen. 2026. LLM Feedback for Topic Model with Preference Optimization and Contrastive Learning. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 6021–6045, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
LLM Feedback for Topic Model with Preference Optimization and Contrastive Learning (Nguyen et al., EMNLP 2026)
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PDF:
https://aclanthology.org/2026.emnlp-main.265.pdf