DARC: Disagreement-Aware Alignment via Risk-Constrained Decoding

Fuente: arXiv
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Hauptverfasser: Zou, Mingxi, Chen, Jiaxiang, Li, Junfan, Liang, Langzhang, Wang, Qifan, Yinghui, Xu, Xu, Zenglin
Format: Preprint
Veröffentlicht: 2026
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author Zou, Mingxi
Chen, Jiaxiang
Li, Junfan
Liang, Langzhang
Wang, Qifan
Yinghui, Xu
Xu, Zenglin
author_facet Zou, Mingxi
Chen, Jiaxiang
Li, Junfan
Liang, Langzhang
Wang, Qifan
Yinghui, Xu
Xu, Zenglin
contents Preference-based alignment methods (e.g., RLHF, DPO) typically optimize a single scalar objective, implicitly averaging over heterogeneous human preferences. In practice, systematic annotator and user-group disagreement makes mean-reward maximization brittle and susceptible to proxy over-optimization. We propose **Disagreement-Aware Alignment via Risk-Constrained Decoding (DARC)**, a retraining-free inference-time method that frames response selection as distributionally robust, risk-sensitive decision making. Given multiple preference samples or scalable disagreement proxies, DARC reranks candidates by maximizing a *KL-robust (entropic)* satisfaction objective, and provides simple deployment controls that cap or penalize the corresponding entropic risk premium relative to the mean, enabling explicit risk budgets without retraining. We provide theoretical characterization linking this decoding rule to principled pessimism and KL-based distributionally robust optimization. Experiments on alignment benchmarks show that DARC reduces disagreement and tail risk while maintaining competitive average quality under noisy, heterogeneous feedback.
format Preprint
id arxiv_https___arxiv_org_abs_2603_08145
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle DARC: Disagreement-Aware Alignment via Risk-Constrained Decoding
Zou, Mingxi
Chen, Jiaxiang
Li, Junfan
Liang, Langzhang
Wang, Qifan
Yinghui, Xu
Xu, Zenglin
Machine Learning
Artificial Intelligence
Preference-based alignment methods (e.g., RLHF, DPO) typically optimize a single scalar objective, implicitly averaging over heterogeneous human preferences. In practice, systematic annotator and user-group disagreement makes mean-reward maximization brittle and susceptible to proxy over-optimization. We propose **Disagreement-Aware Alignment via Risk-Constrained Decoding (DARC)**, a retraining-free inference-time method that frames response selection as distributionally robust, risk-sensitive decision making. Given multiple preference samples or scalable disagreement proxies, DARC reranks candidates by maximizing a *KL-robust (entropic)* satisfaction objective, and provides simple deployment controls that cap or penalize the corresponding entropic risk premium relative to the mean, enabling explicit risk budgets without retraining. We provide theoretical characterization linking this decoding rule to principled pessimism and KL-based distributionally robust optimization. Experiments on alignment benchmarks show that DARC reduces disagreement and tail risk while maintaining competitive average quality under noisy, heterogeneous feedback.
title DARC: Disagreement-Aware Alignment via Risk-Constrained Decoding
topic Machine Learning
Artificial Intelligence
url https://arxiv.org/abs/2603.08145