When Benchmarks Age: Temporal Misalignment through Large Language Model Factuality Evaluation

Xunyi Jiang, Dingyi Chang, Julian McAuley, Xin Xu


Abstract
The rapid evolution of large language models (LLMs) and the real world has outpaced the static nature of widely used evaluation benchmarks, raising concerns about their reliability for evaluating LLM factuality. While substantial works continue to rely on the popular but old benchmarks, their temporal misalignment with real-world facts and modern LLMs, and their effects on LLM factuality evaluation remain underexplored. Therefore, in this work, we present a systematic investigation of this issue by examining five popular factuality benchmarks and eight LLMs released across different years. An up-to-date fact retrieval pipeline and three metrics are tailored to quantify benchmark aging and its impact on LLM factuality evaluation. Experimental results and analysis illustrate that a considerable portion of samples in the widely used factuality benchmarks are outdated, leading to unreliable assessments of LLM factuality. We hope our work can provide a testbed to assess the reliability of a benchmark for LLM factuality evaluation and inspire more research on the benchmark aging issue.
Anthology ID:
2026.eacl-short.37
Volume:
Proceedings of the 19th Conference of the European Chapter of the Association for Computational Linguistics (Volume 2: Short Papers)
Month:
March
Year:
2026
Address:
Rabat, Morocco
Editors:
Vera Demberg, Kentaro Inui, Lluís Marquez
Venue:
EACL
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Publisher:
Association for Computational Linguistics
Note:
Pages:
500–512
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URL:
https://preview.aclanthology.org/ingest-eacl/2026.eacl-short.37/
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Bibkey:
Cite (ACL):
Xunyi Jiang, Dingyi Chang, Julian McAuley, and Xin Xu. 2026. When Benchmarks Age: Temporal Misalignment through Large Language Model Factuality Evaluation. In Proceedings of the 19th Conference of the European Chapter of the Association for Computational Linguistics (Volume 2: Short Papers), pages 500–512, Rabat, Morocco. Association for Computational Linguistics.
Cite (Informal):
When Benchmarks Age: Temporal Misalignment through Large Language Model Factuality Evaluation (Jiang et al., EACL 2026)
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