ERGA: An Explorer–Refiner Game with Backdoor-Adjusted Verdict Aggregation for LLM-based Claim Verification

Wanlong Yu, Feng Liu, Zhiliang Tian, Zhen Huang, Yonghui Wang, Jingyuan Huang, Dongsheng Li


Abstract
LLM-based fact-checking verifies complex claims through decomposition, retrieval, and reasoning aggregation. Existing methods expand verification inputs to cover more factual conditions, but added fragments can be redundant or misleading, compete with decisive evidence, and bias predictions toward surface relevance. Debiasing methods mitigate this bias by estimating shortcut effects from claim-side cues or biased signals in constructed inputs. However, because they calibrate verifier predictions after input construction, they are not designed to repair missing or noisy verification states. Thus, complex fact-checking should balance factual coverage and noise control during verification-state construction. We propose ERGA, an Explorer–Refiner Game with Backdoor-Adjusted Verdict Aggregation. ERGA formulates verification as editable state construction, initializing the state from decomposed verification units, retrieved evidence, and local analyses. It then runs an adversarial Explorer–Refiner game over this state: the Explorer strengthens under-covered factual signals, while the Refiner merges redundancy and separates weak or misleading fragments. Through this game interaction, ERGA obtains a refined state with a better coverage–noise balance and a removed fragment record. For verdict aggregation, ERGA uses the removed-fragment record to condition verifier predictions and aggregates them in a backdoor-adjusted form to reduce residual shortcut effects. Experiments on HoVer and FEVEROUS-S show that ERGA outperforms strong baselines.
Anthology ID:
2026.findings-emnlp.2113
Volume:
Findings of the Association for Computational Linguistics: EMNLP 2026
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
Findings
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
45048–45066
Language:
URL:
https://aclanthology.org/2026.findings-emnlp.2113/
DOI:
Bibkey:
Cite (ACL):
Wanlong Yu, Feng Liu, Zhiliang Tian, Zhen Huang, Yonghui Wang, Jingyuan Huang, and Dongsheng Li. 2026. ERGA: An Explorer–Refiner Game with Backdoor-Adjusted Verdict Aggregation for LLM-based Claim Verification. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 45048–45066, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
ERGA: An Explorer–Refiner Game with Backdoor-Adjusted Verdict Aggregation for LLM-based Claim Verification (Yu et al., Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-emnlp.2113.pdf