Factual State Discovery Benchmark: Evaluating Fact Elicitation in Polish Tax Law

Mateusz Bystroński, Kamil Tagowski, Denis Janiak, Julia Farganus, Lukasz Augustyniak, Monika Kajdanowicz, Tomasz Jan Kajdanowicz


Abstract
Before a tax authority can issue a ruling, it must receive a complete description of the taxpayer’s situation—yet no benchmark measures whether language models can systematically elicit all relevant facts through dialogue.We introduce FSDBench (Factual State Discovery Benchmark), in which a discovery agent questions a simulated taxpayer grounded in a real tax document.The dataset comprises 500 narratives from official Polish tax interpretations, decomposed into 32 874 atomic facts with validated supported precision (97.6%), atomicity (93.8%), and sentence coverage (96.0%).Experiments with four models show that even the best system recovers only 77% of facts on easy samples and under 49% on hard samples after 50 turns.These findings establish conversational fact elicitation as a challenging open problem requiring retrieval-augmented and adaptive questioning strategies.
Anthology ID:
2026.acl-srw.114
Volume:
Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (ACL 2026)
Month:
July
Year:
2026
Address:
San Diego, California, United States
Editors:
Santosh T.Y.S.S., Juan Diego Rodriguez, Ona de Gibert
Venue:
ACL
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
1262–1279
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URL:
https://preview.aclanthology.org/ingest-acl/2026.acl-srw.114/
DOI:
Bibkey:
Cite (ACL):
Mateusz Bystroński, Kamil Tagowski, Denis Janiak, Julia Farganus, Lukasz Augustyniak, Monika Kajdanowicz, and Tomasz Jan Kajdanowicz. 2026. Factual State Discovery Benchmark: Evaluating Fact Elicitation in Polish Tax Law. In Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (ACL 2026), pages 1262–1279, San Diego, California, United States. Association for Computational Linguistics.
Cite (Informal):
Factual State Discovery Benchmark: Evaluating Fact Elicitation in Polish Tax Law (Bystroński et al., ACL 2026)
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https://preview.aclanthology.org/ingest-acl/2026.acl-srw.114.pdf