Dependence-Aware Label Aggregation for LLM-as-a-Judge via Ising Models

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Hauptverfasser: Balasubramanian, Krishnakumar, Podkopaev, Aleksandr, Kasiviswanathan, Shiva Prasad
Format: Preprint
Veröffentlicht: 2026
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author Balasubramanian, Krishnakumar
Podkopaev, Aleksandr
Kasiviswanathan, Shiva Prasad
author_facet Balasubramanian, Krishnakumar
Podkopaev, Aleksandr
Kasiviswanathan, Shiva Prasad
contents Large-scale AI evaluation increasingly relies on aggregating binary judgments from $K$ annotators, including LLMs used as judges. Most classical methods, e.g., Dawid-Skene or (weighted) majority voting, assume annotators are conditionally independent given the true label $Y\in\{0,1\}$, an assumption often violated by LLM judges due to shared data, architectures, prompts, and failure modes. Ignoring such dependencies can yield miscalibrated posteriors and even confidently incorrect predictions. We study label aggregation through a hierarchy of dependence-aware models based on Ising graphical models and latent factors. For class-dependent Ising models, the Bayes log-odds is generally quadratic in votes; for class-independent couplings, it reduces to a linear weighted vote with correlation-adjusted parameters. We present finite-$K$ examples showing that methods based on conditional independence can flip the Bayes label despite matching per-annotator marginals. We prove separation results demonstrating that these methods remain strictly suboptimal as the number of judges grows, incurring nonvanishing excess risk under latent factors. Finally, we evaluate the proposed method on three real-world datasets, demonstrating improved performance over the classical baselines.
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id arxiv_https___arxiv_org_abs_2601_22336
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Dependence-Aware Label Aggregation for LLM-as-a-Judge via Ising Models
Balasubramanian, Krishnakumar
Podkopaev, Aleksandr
Kasiviswanathan, Shiva Prasad
Machine Learning
Methodology
Large-scale AI evaluation increasingly relies on aggregating binary judgments from $K$ annotators, including LLMs used as judges. Most classical methods, e.g., Dawid-Skene or (weighted) majority voting, assume annotators are conditionally independent given the true label $Y\in\{0,1\}$, an assumption often violated by LLM judges due to shared data, architectures, prompts, and failure modes. Ignoring such dependencies can yield miscalibrated posteriors and even confidently incorrect predictions. We study label aggregation through a hierarchy of dependence-aware models based on Ising graphical models and latent factors. For class-dependent Ising models, the Bayes log-odds is generally quadratic in votes; for class-independent couplings, it reduces to a linear weighted vote with correlation-adjusted parameters. We present finite-$K$ examples showing that methods based on conditional independence can flip the Bayes label despite matching per-annotator marginals. We prove separation results demonstrating that these methods remain strictly suboptimal as the number of judges grows, incurring nonvanishing excess risk under latent factors. Finally, we evaluate the proposed method on three real-world datasets, demonstrating improved performance over the classical baselines.
title Dependence-Aware Label Aggregation for LLM-as-a-Judge via Ising Models
topic Machine Learning
Methodology
url https://arxiv.org/abs/2601.22336