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arXiv 2502.04419cs.LGcs.AIcs.CL

理解并缓解基于LLM的数据增强在下游任务中的偏差继承问题

Understanding and Mitigating the Bias Inheritance in LLM-based Data Augmentation on Downstream Tasks

The Chinese University of Hong Kong(香港中文大学);Carnegie Mellon University(卡内基梅隆大学);Institute of Science Tokyo(东京科学大学);UIUC(伊利诺伊大学厄巴纳-香槟分校);UC Santa Barbara(加利福尼亚大学圣巴巴拉分校);William & Mary(威廉玛丽学院)

Miaomiao Li, Hao Chen, Yang Wang, Tingyuan Zhu, Weijia Zhang, Kaijie Zhu, Kam-Fai Wong, Jindong Wang

AI总结:

本文首次系统研究LLM数据增强中的偏差继承现象,通过10个任务和6种偏差类型的实验揭示其影响机制,并提出基于token、mask和loss的三种缓解策略。

摘要:

通过大语言模型(LLMs)自身生成合成数据集已成为提升LLM性能的一种有前景的方法。然而,LLMs本质上会反映其训练数据中存在的偏差,这带来了一个关键挑战:当这些模型生成用于训练的合成数据时,它们可能会传播并放大其固有偏差,从而显著影响模型在下游任务上的公平性和鲁棒性——我们将这一现象称为偏差继承。本文首次对偏差继承的理解、分析和缓解进行了系统性研究。我们通过使用由原始数据和LLM增强数据组成的组合数据集对LLMs进行微调来研究该问题,其中偏差比率表示增强数据所占的比例。通过在10个分类和生成任务上的系统性实验,我们分析了6种不同类型的偏差在不同偏差比率下的表现。我们的结果表明,偏差继承对下游任务具有细微的影响,对分类任务和生成任务的影响方式不同。随后,我们的分析识别出三个关键的不对齐因素:价值观不对齐、群体数据不对齐和数据分布不对齐。基于这些见解,我们提出了三种缓解策略:基于token的方法、基于mask的方法和基于loss的方法。实验表明,这些策略在不同任务和偏差类型上的效果也各不相同,表明完全缓解偏差继承面临重大挑战。我们希望这项工作能为LLM数据增强研究提供有价值的见解。

英文摘要:

Generating synthetic datasets via large language models (LLMs) themselves has emerged as a promising approach to improve LLM performance. However, LLMs inherently reflect biases present in their training data, leading to a critical challenge: when these models generate synthetic data for training, they may propagate and amplify their inherent biases that can significantly impact model fairness and robustness on downstream tasks--a phenomenon we term bias inheritance. This work presents the first systematic investigation in understanding, analyzing, and mitigating bias inheritance. We study this problem by fine-tuning LLMs with a combined dataset consisting of original and LLM-augmented data, where bias ratio represents the proportion of augmented data. Through systematic experiments across 10 classification and generation tasks, we analyze how 6 different types of biases manifest at varying bias ratios. Our results reveal that bias inheritance has nuanced effects on downstream tasks, influencing both classification tasks and generation tasks differently. Then, our analysis identifies three key misalignment factors: misalignment of values, group data, and data distributions. Based on these insights, we propose three mitigation strategies: token-based, mask-based, and loss-based approaches. Experiments demonstrate that these strategies also work differently on various tasks and bias, indicating the substantial challenges to fully mitigate bias inheritance. We hope this work can provide valuable insights to the research of LLM data augmentation.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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