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ZENODO
Preprint . 2026
License: CC BY
Data sources: ZENODO
ZENODO
Preprint . 2026
License: CC BY
Data sources: Datacite
ZENODO
Preprint . 2026
License: CC BY
Data sources: Datacite
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Beyond Benchmarks: Disagreement Among Frontier LLMs on Real-World Fact-Checks

Authors: Jordanov, Kosta;

Beyond Benchmarks: Disagreement Among Frontier LLMs on Real-World Fact-Checks

Abstract

On 67% of 1,000 recent real-user fact-check claims, a panel of five frontier LLMs splits — at least one model dissents from the majority verdict, or no strict majority forms at all. The five models (GPT-5.4, Claude Opus 4.7, Gemini 3 Pro, Gemini 3 Pro + Search, Sonar Pro) were each given the same claim and asked to pick a verdict from a 4-bucket rubric (True / Mostly True / Misleading / False). Because exactly one bucket can be correct per claim, any disagreement among the panel means at least one model is label-inconsistent. Key findings: 67% of claims (672/1,000; 95% CI 64–70%) have at least one frontier model dissenting from the panel majority, or no strict majority forming at all. 34% of claims (343/1,000; 95% CI 31–37%) involve a substantive disagreement — a ≥2-bucket gap between the most-disagreeing pair of frontier verdicts. Krippendorff's α (ordinal) = 0.639 across 5 raters on 1,000 items — nontrivial but limited agreement. Unanimity concentrates at the True/False poles: of 328 unanimous claims, only 4 are unanimous-Misleading and 0 are unanimous-Mostly-True. The claims are real recent submissions to Lenz, a fact-checking platform — not curated benchmarks — so the disagreement is contamination-resistant by construction. No LLM grader; all measurements derive from direct parsed-label equality across the 5 verdicts. Wilson 95% CIs on every reported rate. This deposit contains the v1.0 PDF snapshot. Full per-claim CSV, HTML rendering, methodology, and changelog: https://lenz.io/research/llm-disagreement

Keywords

benchmark contamination, frontier model evaluation, LLM evaluation, LLM-as-judge, LLM disagreement, fact-checking

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selected citations
These citations are derived from selected sources.
This is an alternative to the "Influence" indicator, which also reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically).
BIP!Citations provided by BIP!
popularity
This indicator reflects the "current" impact/attention (the "hype") of an article in the research community at large, based on the underlying citation network.
BIP!Popularity provided by BIP!
influence
This indicator reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically).
BIP!Influence provided by BIP!
impulse
This indicator reflects the initial momentum of an article directly after its publication, based on the underlying citation network.
BIP!Impulse provided by BIP!
0
Average
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