OxEnsemble: Fair Ensembles for Low-Data Classification

Fuente: arXiv
Saved in:
Bibliographic Details
Main Authors: Rystrøm, Jonathan, Fu, Zihao, Russell, Chris
Format: Preprint
Published: 2025
Subjects:
Online Access:
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1866917393712807936
author Rystrøm, Jonathan
Fu, Zihao
Russell, Chris
author_facet Rystrøm, Jonathan
Fu, Zihao
Russell, Chris
contents We address the problem of fair classification in settings where data is scarce and unbalanced across demographic groups. Such low-data regimes are common in domains like medical imaging, where false negatives can have fatal consequences. We propose a novel approach \emph{OxEnsemble} for efficiently training ensembles and enforcing fairness in these low-data regimes. Unlike other approaches, we aggregate predictions across ensemble members, each trained to satisfy fairness constraints. By construction, \emph{OxEnsemble} is both data-efficient -- carefully reusing held-out data to enforce fairness reliably -- and compute-efficient, requiring little more compute than used to fine-tune or evaluate an existing model. We validate this approach with new theoretical guarantees. Experimentally, our approach yields more consistent outcomes and stronger fairness-accuracy trade-offs than existing methods across multiple challenging medical imaging classification datasets.
format Preprint
id arxiv_https___arxiv_org_abs_2512_09665
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle OxEnsemble: Fair Ensembles for Low-Data Classification
Rystrøm, Jonathan
Fu, Zihao
Russell, Chris
Computer Vision and Pattern Recognition
Computers and Society
Machine Learning
We address the problem of fair classification in settings where data is scarce and unbalanced across demographic groups. Such low-data regimes are common in domains like medical imaging, where false negatives can have fatal consequences. We propose a novel approach \emph{OxEnsemble} for efficiently training ensembles and enforcing fairness in these low-data regimes. Unlike other approaches, we aggregate predictions across ensemble members, each trained to satisfy fairness constraints. By construction, \emph{OxEnsemble} is both data-efficient -- carefully reusing held-out data to enforce fairness reliably -- and compute-efficient, requiring little more compute than used to fine-tune or evaluate an existing model. We validate this approach with new theoretical guarantees. Experimentally, our approach yields more consistent outcomes and stronger fairness-accuracy trade-offs than existing methods across multiple challenging medical imaging classification datasets.
title OxEnsemble: Fair Ensembles for Low-Data Classification
topic Computer Vision and Pattern Recognition
Computers and Society
Machine Learning
url https://arxiv.org/abs/2512.09665