When Facts Change: Probing LLMs on Evolving Knowledge with evolveQA

Nishanth Sridhar Nakshatri, Shamik Roy, Manoj Ghuhan Arivazhagan, Hanhan Zhou, Vinayshekhar Bannihatti Kumar, Rashmi Gangadharaiah


Abstract
LLMs often fail to handle temporal knowledge conflicts–contradictions that arise when facts evolve over time within their training data. Existing benchmarks often rely on structured sources such as Wikidata, where changes are directly exposed through versioned snapshots, and rarely account for differences in model knowledge cut-offs, limiting fair evaluation across LLMs released at different times. We introduce a novel framework for automatically constructing temporal knowledge probing benchmarks from unstructured, time-stamped corpora by discovering evolving knowledge through salient entities, concepts, and attributes; and using this structure to generate grounded questions with gold answers aligned to model cut-off dates. Using this framework, we construct **evolveQA**, spanning 3 domains: AWS service updates, Azure platform changes, and WHO Disease Outbreak News reports. Evaluating 12 open- and closed-source LLMs across 3 probing formats, we find performance drops of up to 31% on **evolveQA** compared to static knowledge questions, showing that LLMs struggle to recall temporally updated facts even when such knowledge is available in their parameters.
Anthology ID:
2026.emnlp-main.2373
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
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Pages:
53864–53893
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URL:
https://aclanthology.org/2026.emnlp-main.2373/
DOI:
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Cite (ACL):
Nishanth Sridhar Nakshatri, Shamik Roy, Manoj Ghuhan Arivazhagan, Hanhan Zhou, Vinayshekhar Bannihatti Kumar, and Rashmi Gangadharaiah. 2026. When Facts Change: Probing LLMs on Evolving Knowledge with evolveQA. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 53864–53893, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
When Facts Change: Probing LLMs on Evolving Knowledge with evolveQA (Nakshatri et al., EMNLP 2026)
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https://aclanthology.org/2026.emnlp-main.2373.pdf