Deep Bayesian Active Learning for Preference Modeling in Large Language Models

TL;DR

This paper introduces BAL-PM, a Bayesian active learning method that efficiently selects informative data points for preference modeling in large language models, significantly reducing labeling costs.

Contribution

The paper proposes a novel stochastic acquisition policy, BAL-PM, that improves preference data selection by balancing uncertainty and entropy, outperforming previous methods.

Findings

BAL-PM reduces preference label requirements by 33% to 68%.

It outperforms previous stochastic Bayesian acquisition policies.

Demonstrates effectiveness on popular human preference datasets.

Abstract

Leveraging human preferences for steering the behavior of Large Language Models (LLMs) has demonstrated notable success in recent years. Nonetheless, data selection and labeling are still a bottleneck for these systems, particularly at large scale. Hence, selecting the most informative points for acquiring human feedback may considerably reduce the cost of preference labeling and unleash the further development of LLMs. Bayesian Active Learning provides a principled framework for addressing this challenge and has demonstrated remarkable success in diverse settings. However, previous attempts to employ it for Preference Modeling did not meet such expectations. In this work, we identify that naive epistemic uncertainty estimation leads to the acquisition of redundant samples. We address this by proposing the Bayesian Active Learner for Preference Modeling (BAL-PM), a novel stochastic acquisition policy that not only targets points of high epistemic uncertainty according to the preference model but also seeks to maximize the entropy of the acquired prompt distribution in the feature space spanned by the employed LLM. Notably, our experiments demonstrate that BAL-PM requires 33% to 68% fewer preference labels in two popular human preference datasets and exceeds previous stochastic Bayesian acquisition policies.