Fairness-Aware Low-Rank Adaptation Under Demographic Privacy Constraints

Fuente: arXiv
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Main Authors: Kamalaruban, Parameswaran, Anderson, Mark, Burrell, Stuart, Madigan, Maeve, Skalski, Piotr, Sutton, David
Format: Preprint
Published: 2025
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author Kamalaruban, Parameswaran
Anderson, Mark
Burrell, Stuart
Madigan, Maeve
Skalski, Piotr
Sutton, David
author_facet Kamalaruban, Parameswaran
Anderson, Mark
Burrell, Stuart
Madigan, Maeve
Skalski, Piotr
Sutton, David
contents Pre-trained foundation models can be adapted for specific tasks using Low-Rank Adaptation (LoRA). However, the fairness properties of these adapted classifiers remain underexplored. Existing fairness-aware fine-tuning methods rely on direct access to sensitive attributes or their predictors, but in practice, these sensitive attributes are often held under strict consumer privacy controls, and neither the attributes nor their predictors are available to model developers, hampering the development of fair models. To address this issue, we introduce a set of LoRA-based fine-tuning methods that can be trained in a distributed fashion, where model developers and fairness auditors collaborate without sharing sensitive attributes or predictors. In this paper, we evaluate three such methods - sensitive unlearning, adversarial training, and orthogonality loss - against a fairness-unaware baseline, using experiments on the CelebA and UTK-Face datasets with an ImageNet pre-trained ViT-Base model. We find that orthogonality loss consistently reduces bias while maintaining or improving utility, whereas adversarial training improves False Positive Rate Parity and Demographic Parity in some cases, and sensitive unlearning provides no clear benefit. In tasks where significant biases are present, distributed fairness-aware fine-tuning methods can effectively eliminate bias without compromising consumer privacy and, in most cases, improve model utility.
format Preprint
id arxiv_https___arxiv_org_abs_2503_05684
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Fairness-Aware Low-Rank Adaptation Under Demographic Privacy Constraints
Kamalaruban, Parameswaran
Anderson, Mark
Burrell, Stuart
Madigan, Maeve
Skalski, Piotr
Sutton, David
Machine Learning
Computer Vision and Pattern Recognition
Pre-trained foundation models can be adapted for specific tasks using Low-Rank Adaptation (LoRA). However, the fairness properties of these adapted classifiers remain underexplored. Existing fairness-aware fine-tuning methods rely on direct access to sensitive attributes or their predictors, but in practice, these sensitive attributes are often held under strict consumer privacy controls, and neither the attributes nor their predictors are available to model developers, hampering the development of fair models. To address this issue, we introduce a set of LoRA-based fine-tuning methods that can be trained in a distributed fashion, where model developers and fairness auditors collaborate without sharing sensitive attributes or predictors. In this paper, we evaluate three such methods - sensitive unlearning, adversarial training, and orthogonality loss - against a fairness-unaware baseline, using experiments on the CelebA and UTK-Face datasets with an ImageNet pre-trained ViT-Base model. We find that orthogonality loss consistently reduces bias while maintaining or improving utility, whereas adversarial training improves False Positive Rate Parity and Demographic Parity in some cases, and sensitive unlearning provides no clear benefit. In tasks where significant biases are present, distributed fairness-aware fine-tuning methods can effectively eliminate bias without compromising consumer privacy and, in most cases, improve model utility.
title Fairness-Aware Low-Rank Adaptation Under Demographic Privacy Constraints
topic Machine Learning
Computer Vision and Pattern Recognition
url https://arxiv.org/abs/2503.05684