Permutation-Consensus Listwise Judging for Robust Factuality Evaluation

Fuente: arXiv
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Autores principales: Huang, Tianyi, Huang, Nathan, Tang, Justin, Chen, Wenqian, Fan, Elsa
Formato: Preprint
Publicado: 2026
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author Huang, Tianyi
Huang, Nathan
Tang, Justin
Chen, Wenqian
Fan, Elsa
author_facet Huang, Tianyi
Huang, Nathan
Tang, Justin
Chen, Wenqian
Fan, Elsa
contents Large language models (LLMs) are now widely used as judges, yet their decisions can change under presentation choices that should be irrelevant. We study one such source of instability: candidate-order sensitivity in listwise factuality evaluation, where several answers can look similarly polished while differing substantially in hallucination risk. We introduce PCFJudge, an inference-time method that reruns the same factuality-first listwise prompt over multiple orderings of the same candidate set and aggregates the resulting scores, ranks, and uncertainty signals into a single consensus decision. On RewardBench 2 Factuality, the final seven-permutation aggregate (K=7) improves top-1 selection accuracy from 86.00% to 91.33% with GPT-5.4 and from 86.33% to 89.67% with Claude Sonnet 4.6. These results suggest that candidate order can be a meaningful source of factuality-judging error and that marginalizing over this nuisance variation can improve the reliability of LLM evaluation.
format Preprint
id arxiv_https___arxiv_org_abs_2603_20562
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Permutation-Consensus Listwise Judging for Robust Factuality Evaluation
Huang, Tianyi
Huang, Nathan
Tang, Justin
Chen, Wenqian
Fan, Elsa
Computation and Language
Artificial Intelligence
Large language models (LLMs) are now widely used as judges, yet their decisions can change under presentation choices that should be irrelevant. We study one such source of instability: candidate-order sensitivity in listwise factuality evaluation, where several answers can look similarly polished while differing substantially in hallucination risk. We introduce PCFJudge, an inference-time method that reruns the same factuality-first listwise prompt over multiple orderings of the same candidate set and aggregates the resulting scores, ranks, and uncertainty signals into a single consensus decision. On RewardBench 2 Factuality, the final seven-permutation aggregate (K=7) improves top-1 selection accuracy from 86.00% to 91.33% with GPT-5.4 and from 86.33% to 89.67% with Claude Sonnet 4.6. These results suggest that candidate order can be a meaningful source of factuality-judging error and that marginalizing over this nuisance variation can improve the reliability of LLM evaluation.
title Permutation-Consensus Listwise Judging for Robust Factuality Evaluation
topic Computation and Language
Artificial Intelligence
url https://arxiv.org/abs/2603.20562