InCo-DPO: Balancing Distribution Shift and Data Quality for Enhanced Preference Optimization

Fuente: arXiv
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Autori principali: Wang, Yunan, Li, Jijie, Zhang, Bo-Wen, Wang, Liangdong, Liu, Guang
Natura: Preprint
Pubblicazione: 2025
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author Wang, Yunan
Li, Jijie
Zhang, Bo-Wen
Wang, Liangdong
Liu, Guang
author_facet Wang, Yunan
Li, Jijie
Zhang, Bo-Wen
Wang, Liangdong
Liu, Guang
contents Direct Preference Optimization (DPO) optimizes language models to align with human preferences. Utilizing on-policy samples, generated directly by the policy model, typically results in better performance due to its distribution consistency with the model compared to off-policy samples. This paper identifies the quality of candidate preference samples as another critical factor. While the quality of on-policy data is inherently constrained by the capabilities of the policy model, off-policy data, which can be derived from diverse sources, offers greater potential for quality despite experiencing distribution shifts. However, current research mostly relies on on-policy data and neglects the value of off-policy data in terms of data quality, due to the challenge posed by distribution shift. In this paper, we propose InCo-DPO, an efficient method for synthesizing preference data by integrating on-policy and off-policy data, allowing dynamic adjustments to balance distribution shifts and data quality, thus finding an optimal trade-off. Consequently, InCo-DPO overcomes the limitations of distribution shifts in off-policy data and the quality constraints of on-policy data. We evaluated InCo-DPO with the Alpaca-Eval 2.0 and Arena-Hard benchmarks. Experimental results demonstrate that our approach not only outperforms both on-policy and off-policy data but also achieves a state-of-the-art win rate of 60.8 on Arena-Hard with the vanilla DPO using Gemma-2 model.
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id arxiv_https___arxiv_org_abs_2503_15880
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle InCo-DPO: Balancing Distribution Shift and Data Quality for Enhanced Preference Optimization
Wang, Yunan
Li, Jijie
Zhang, Bo-Wen
Wang, Liangdong
Liu, Guang
Machine Learning
Computation and Language
Direct Preference Optimization (DPO) optimizes language models to align with human preferences. Utilizing on-policy samples, generated directly by the policy model, typically results in better performance due to its distribution consistency with the model compared to off-policy samples. This paper identifies the quality of candidate preference samples as another critical factor. While the quality of on-policy data is inherently constrained by the capabilities of the policy model, off-policy data, which can be derived from diverse sources, offers greater potential for quality despite experiencing distribution shifts. However, current research mostly relies on on-policy data and neglects the value of off-policy data in terms of data quality, due to the challenge posed by distribution shift. In this paper, we propose InCo-DPO, an efficient method for synthesizing preference data by integrating on-policy and off-policy data, allowing dynamic adjustments to balance distribution shifts and data quality, thus finding an optimal trade-off. Consequently, InCo-DPO overcomes the limitations of distribution shifts in off-policy data and the quality constraints of on-policy data. We evaluated InCo-DPO with the Alpaca-Eval 2.0 and Arena-Hard benchmarks. Experimental results demonstrate that our approach not only outperforms both on-policy and off-policy data but also achieves a state-of-the-art win rate of 60.8 on Arena-Hard with the vanilla DPO using Gemma-2 model.
title InCo-DPO: Balancing Distribution Shift and Data Quality for Enhanced Preference Optimization
topic Machine Learning
Computation and Language
url https://arxiv.org/abs/2503.15880