ThinknCheck: Grounded Claim Verification with Compact, Reasoning-Driven, and Interpretable Models

Fuente: arXiv
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Main Authors: Rao, Delip, Han, Feijiang, Callison-Burch, Chris
Format: Preprint
Published: 2026
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author Rao, Delip
Han, Feijiang
Callison-Burch, Chris
author_facet Rao, Delip
Han, Feijiang
Callison-Burch, Chris
contents We present ThinknCheck, a 1B-parameter verifier for grounded claim verification that first produces a short, structured rationale and then a binary verdict. We construct LLMAggreFact-Think, a 24.1k reasoning-augmented training set derived from LLMAggreFact, and fine-tune a 4-bit Gemma3 model to follow this format. On LLMAggreFact, ThinknCheck attains 78.1 balanced accuracy (BAcc), surpassing MiniCheck-7B (77.4) with 7x fewer parameters; removing the reasoning step reduces BAcc to 57.5. On SciFact, ThinknCheck reaches 64.7 BAcc, a +14.7 absolute gain over MiniCheck-7B. By contrast, zero-shot chain-of-thought on the base Gemma3-1B harms accuracy relative to direct answers, and preference optimization with a simple format+accuracy reward underperforms supervised reasoning. To probe the latter, we introduce GSMClaims and a domain-specialized variant, ThinknCheck-Science, which improves across benchmarks, including 61.0\% accuracy on GSMClaims. Overall, explicit, supervised reasoning enables compact verifiers that are competitive while remaining resource-efficient and interpretable.
format Preprint
id arxiv_https___arxiv_org_abs_2604_01652
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle ThinknCheck: Grounded Claim Verification with Compact, Reasoning-Driven, and Interpretable Models
Rao, Delip
Han, Feijiang
Callison-Burch, Chris
Artificial Intelligence
Computation and Language
We present ThinknCheck, a 1B-parameter verifier for grounded claim verification that first produces a short, structured rationale and then a binary verdict. We construct LLMAggreFact-Think, a 24.1k reasoning-augmented training set derived from LLMAggreFact, and fine-tune a 4-bit Gemma3 model to follow this format. On LLMAggreFact, ThinknCheck attains 78.1 balanced accuracy (BAcc), surpassing MiniCheck-7B (77.4) with 7x fewer parameters; removing the reasoning step reduces BAcc to 57.5. On SciFact, ThinknCheck reaches 64.7 BAcc, a +14.7 absolute gain over MiniCheck-7B. By contrast, zero-shot chain-of-thought on the base Gemma3-1B harms accuracy relative to direct answers, and preference optimization with a simple format+accuracy reward underperforms supervised reasoning. To probe the latter, we introduce GSMClaims and a domain-specialized variant, ThinknCheck-Science, which improves across benchmarks, including 61.0\% accuracy on GSMClaims. Overall, explicit, supervised reasoning enables compact verifiers that are competitive while remaining resource-efficient and interpretable.
title ThinknCheck: Grounded Claim Verification with Compact, Reasoning-Driven, and Interpretable Models
topic Artificial Intelligence
Computation and Language
url https://arxiv.org/abs/2604.01652