When Wording Steers the Evaluation: Framing Bias in LLM judges

Fuente: arXiv
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Main Authors: Hwang, Yerin, Lee, Dongryeol, Kang, Taegwan, Lee, Minwoo, Jung, Kyomin
Format: Preprint
Published: 2026
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author Hwang, Yerin
Lee, Dongryeol
Kang, Taegwan
Lee, Minwoo
Jung, Kyomin
author_facet Hwang, Yerin
Lee, Dongryeol
Kang, Taegwan
Lee, Minwoo
Jung, Kyomin
contents Large language models (LLMs) are known to produce varying responses depending on prompt phrasing, indicating that subtle guidance in phrasing can steer their answers. However, the impact of this framing bias on LLM-based evaluation, where models are expected to make stable and impartial judgments, remains largely underexplored. Drawing inspiration from the framing effect in psychology, we systematically investigate how deliberate prompt framing skews model judgments across four high-stakes evaluation tasks. We design symmetric prompts using predicate-positive and predicate-negative constructions and demonstrate that such framing induces significant discrepancies in model outputs. Across 14 LLM judges, we observe clear susceptibility to framing, with model families showing distinct tendencies toward agreement or rejection. These findings suggest that framing bias is a structural property of current LLM-based evaluation systems, underscoring the need for framing-aware protocols.
format Preprint
id arxiv_https___arxiv_org_abs_2601_13537
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle When Wording Steers the Evaluation: Framing Bias in LLM judges
Hwang, Yerin
Lee, Dongryeol
Kang, Taegwan
Lee, Minwoo
Jung, Kyomin
Computation and Language
Artificial Intelligence
Large language models (LLMs) are known to produce varying responses depending on prompt phrasing, indicating that subtle guidance in phrasing can steer their answers. However, the impact of this framing bias on LLM-based evaluation, where models are expected to make stable and impartial judgments, remains largely underexplored. Drawing inspiration from the framing effect in psychology, we systematically investigate how deliberate prompt framing skews model judgments across four high-stakes evaluation tasks. We design symmetric prompts using predicate-positive and predicate-negative constructions and demonstrate that such framing induces significant discrepancies in model outputs. Across 14 LLM judges, we observe clear susceptibility to framing, with model families showing distinct tendencies toward agreement or rejection. These findings suggest that framing bias is a structural property of current LLM-based evaluation systems, underscoring the need for framing-aware protocols.
title When Wording Steers the Evaluation: Framing Bias in LLM judges
topic Computation and Language
Artificial Intelligence
url https://arxiv.org/abs/2601.13537