Less is More: Improving LLM Alignment via Preference Data Selection

Fuente: arXiv
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Autores principales: Deng, Xun, Zhong, Han, Ai, Rui, Feng, Fuli, Wang, Zheng, He, Xiangnan
Formato: Preprint
Publicado: 2025
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author Deng, Xun
Zhong, Han
Ai, Rui
Feng, Fuli
Wang, Zheng
He, Xiangnan
author_facet Deng, Xun
Zhong, Han
Ai, Rui
Feng, Fuli
Wang, Zheng
He, Xiangnan
contents Direct Preference Optimization (DPO) has emerged as a promising approach for aligning large language models with human preferences. While prior work mainly extends DPO from the aspect of the objective function, we instead improve DPO from the largely overlooked but critical aspect of data selection. Specifically, we address the issue of parameter shrinkage caused by noisy data by proposing a novel margin-maximization principle for dataset curation in DPO training. To further mitigate the noise in different reward models, we propose a Bayesian Aggregation approach that unifies multiple margin sources (external and implicit) into a single preference probability. Extensive experiments in diverse settings demonstrate the consistently high data efficiency of our approach. Remarkably, by using just 10\% of the Ultrafeedback dataset, our approach achieves 3\% to 8\% improvements across various Llama, Mistral, and Qwen models on the AlpacaEval2 benchmark. Furthermore, our approach seamlessly extends to iterative DPO, yielding a roughly 3\% improvement with 25\% online data, revealing the high redundancy in this presumed high-quality data construction manner. These results highlight the potential of data selection strategies for advancing preference optimization.
format Preprint
id arxiv_https___arxiv_org_abs_2502_14560
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Less is More: Improving LLM Alignment via Preference Data Selection
Deng, Xun
Zhong, Han
Ai, Rui
Feng, Fuli
Wang, Zheng
He, Xiangnan
Machine Learning
Artificial Intelligence
Computation and Language
Direct Preference Optimization (DPO) has emerged as a promising approach for aligning large language models with human preferences. While prior work mainly extends DPO from the aspect of the objective function, we instead improve DPO from the largely overlooked but critical aspect of data selection. Specifically, we address the issue of parameter shrinkage caused by noisy data by proposing a novel margin-maximization principle for dataset curation in DPO training. To further mitigate the noise in different reward models, we propose a Bayesian Aggregation approach that unifies multiple margin sources (external and implicit) into a single preference probability. Extensive experiments in diverse settings demonstrate the consistently high data efficiency of our approach. Remarkably, by using just 10\% of the Ultrafeedback dataset, our approach achieves 3\% to 8\% improvements across various Llama, Mistral, and Qwen models on the AlpacaEval2 benchmark. Furthermore, our approach seamlessly extends to iterative DPO, yielding a roughly 3\% improvement with 25\% online data, revealing the high redundancy in this presumed high-quality data construction manner. These results highlight the potential of data selection strategies for advancing preference optimization.
title Less is More: Improving LLM Alignment via Preference Data Selection
topic Machine Learning
Artificial Intelligence
Computation and Language
url https://arxiv.org/abs/2502.14560