NE-R1: Enhancing Named Entity Recognition Model via Reinforcement Learning

Meixuan Chen, Hehan Li, Ruizhi Zhao, Xin Lu, Peizhi xu, Liwei Qian, LI Meifang, Shuanglong li, Hanmeng Liu, Xin Pei, Yanbiao Ma


Abstract
Named Entity Recognition (NER) has achieved substantial progress since the advent of large language models (LLMs). Nevertheless, the recognition of long-tail and domain-specific entities remains challenging due to the deficiency in parametric knowledge. Retrieval-augmented generation (RAG) offers a promising remedy by injecting external knowledge, but it also introduces noise and unnecessary cost when dealing with familiar cases. In this paper, we propose NE-R1, a novel framework for adaptive retrieval-augmented NER. We design a “retrieval-on-demand” mechanism for NER. Then we integrate it into models by a two-stage training method: (1) multi-task instruction tuning initialization; (2) end-to-end RL optimization with CoT. To achieve reasonable selection between parameterized and external knowledge, we design a multi-dimensional reward considering both accuracy and retrieval benefit. NE-R1 achieves state-of-the-art performance on various benchmarks, with average improvements of 2.52 F1 points in in-domain evaluation and 1.18 F1 points in zero-shot cross-domain evaluation.
Anthology ID:
2026.emnlp-main.2025
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:
46132–46149
Language:
URL:
https://aclanthology.org/2026.emnlp-main.2025/
DOI:
Bibkey:
Cite (ACL):
Meixuan Chen, Hehan Li, Ruizhi Zhao, Xin Lu, Peizhi xu, Liwei Qian, LI Meifang, Shuanglong li, Hanmeng Liu, Xin Pei, and Yanbiao Ma. 2026. NE-R1: Enhancing Named Entity Recognition Model via Reinforcement Learning. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 46132–46149, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
NE-R1: Enhancing Named Entity Recognition Model via Reinforcement Learning (Chen et al., EMNLP 2026)
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PDF:
https://aclanthology.org/2026.emnlp-main.2025.pdf