Lightweight Robust Direct Preference Optimization

Fuente: arXiv
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Autori principali: Kim, Cheol Woo, Verma, Shresth, Tec, Mauricio, Tambe, Milind
Natura: Preprint
Pubblicazione: 2025
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author Kim, Cheol Woo
Verma, Shresth
Tec, Mauricio
Tambe, Milind
author_facet Kim, Cheol Woo
Verma, Shresth
Tec, Mauricio
Tambe, Milind
contents Direct Preference Optimization (DPO) has become a popular method for fine-tuning large language models (LLMs) due to its stability and simplicity. However, it is also known to be sensitive to noise in the data and prone to overfitting. Recent works have proposed using distributionally robust optimization (DRO) to address potential noise and distributional shift in the data. However, these methods often suffer from excessive conservatism and high computational cost. We propose DPO-PRO (DPO with Preference Robustness), a robust fine-tuning algorithm based on DPO which accounts for uncertainty in the preference distribution through a lightweight DRO formulation. Unlike prior DRO-based variants, DPO-PRO focuses solely on uncertainty in preferences, avoiding unnecessary conservatism and incurring negligible computational overhead. We further show that DPO-PRO is equivalent to a regularized DPO objective that penalizes model overconfidence under weak preference signals. We evaluate DPO-PRO on standard alignment benchmarks and a real-world public health task. Experimental results show that our method consistently improves robustness to noisy preference signals compared to existing DPO variants.
format Preprint
id arxiv_https___arxiv_org_abs_2510_23590
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Lightweight Robust Direct Preference Optimization
Kim, Cheol Woo
Verma, Shresth
Tec, Mauricio
Tambe, Milind
Machine Learning
Direct Preference Optimization (DPO) has become a popular method for fine-tuning large language models (LLMs) due to its stability and simplicity. However, it is also known to be sensitive to noise in the data and prone to overfitting. Recent works have proposed using distributionally robust optimization (DRO) to address potential noise and distributional shift in the data. However, these methods often suffer from excessive conservatism and high computational cost. We propose DPO-PRO (DPO with Preference Robustness), a robust fine-tuning algorithm based on DPO which accounts for uncertainty in the preference distribution through a lightweight DRO formulation. Unlike prior DRO-based variants, DPO-PRO focuses solely on uncertainty in preferences, avoiding unnecessary conservatism and incurring negligible computational overhead. We further show that DPO-PRO is equivalent to a regularized DPO objective that penalizes model overconfidence under weak preference signals. We evaluate DPO-PRO on standard alignment benchmarks and a real-world public health task. Experimental results show that our method consistently improves robustness to noisy preference signals compared to existing DPO variants.
title Lightweight Robust Direct Preference Optimization
topic Machine Learning
url https://arxiv.org/abs/2510.23590