LPFQA: A Long-Tail Professional Forum-based Benchmark for LLM Evaluation

Liya Zhu, Peizhuang Cong, Jingzhe Ding, Aowei Ji, Wenya Wu, Jiani Hou, Chunjie Wu, Xiang Gao, Jingkai Liu, Zhou Huan, XueLei Sun, Yang Yang, Jianpeng Jiao, Liang HU, Xinjie Chen, Jiashuo Liu, Tong Yang, Zaiyuan Wang, Ge Zhang, Wenhao Huang


Abstract
Large Language Models (LLMs) perform well on standard reasoning and question-answering benchmarks, yet such evaluations often fail to capture their ability to handle long-tail, expertise-intensive knowledge in real-world professional scenarios. We introduce LPFQA, a long-tail knowledge benchmark derived from authentic professional forum discussions, covering 7 academic and industrial domains with 430 curated tasks grounded in practical expertise. LPFQA evaluates specialized reasoning, domain-specific terminology understanding, and contextual interpretation, and adopts a hierarchical difficulty structure to ensure semantic clarity and uniquely identifiable answers. Experiments on over multiple mainstream LLMs reveal substantial performance gaps, particularly on tasks requiring deep domain reasoning, exposing limitations overlooked by existing benchmarks. Overall, LPFQA provides an authentic and discriminative evaluation framework that complements prior benchmarks and informs future LLM development. Our data is available at https://huggingface.co/datasets/m-a-p/LPFQA.
Anthology ID:
2026.emnlp-main.1741
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:
39705–39726
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URL:
https://aclanthology.org/2026.emnlp-main.1741/
DOI:
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Cite (ACL):
Liya Zhu, Peizhuang Cong, Jingzhe Ding, Aowei Ji, Wenya Wu, Jiani Hou, Chunjie Wu, Xiang Gao, Jingkai Liu, Zhou Huan, XueLei Sun, Yang Yang, Jianpeng Jiao, Liang HU, Xinjie Chen, Jiashuo Liu, Tong Yang, Zaiyuan Wang, Ge Zhang, and Wenhao Huang. 2026. LPFQA: A Long-Tail Professional Forum-based Benchmark for LLM Evaluation. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 39705–39726, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
LPFQA: A Long-Tail Professional Forum-based Benchmark for LLM Evaluation (Zhu et al., EMNLP 2026)
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https://aclanthology.org/2026.emnlp-main.1741.pdf