Does Data-Efficient Generalization Exacerbate Bias in Foundation Models?
Dilermando Queiroz, Anderson Carlos, Maíra Fatoretto, Luis Filipe Nakayama, André Anjos, Lilian Berton
TL;DR
The paper evaluates bias in retinal Foundation Models when fine-tuning with limited data on BRSET, comparing RetFound to a supervised baseline. It shows that self-supervised pretraining can mitigate bias compared to supervision, but data-efficient regimes can increase age-related disparities, highlighting a crucial trade-off between utility and fairness. The study introduces fairness metrics adapted from MedFair 2023 and demonstrates that stratified sampling and broader validation are needed for equitable deployment of foundation models in medical imaging. These findings have practical implications for deploying data-efficient medical AI in underrepresented populations and stress the importance of fairness considerations in model selection and data curation.
Abstract
Foundation models have emerged as robust models with label efficiency in diverse domains. In medical imaging, these models contribute to the advancement of medical diagnoses due to the difficulty in obtaining labeled data. However, it is unclear whether using a large amount of unlabeled data, biased by the presence of sensitive attributes during pre-training, influences the fairness of the model. This research examines the bias in the Foundation model (RetFound) when it is applied to fine-tune the Brazilian Multilabel Ophthalmological Dataset (BRSET), which has a different population than the pre-training dataset. The model evaluation, in comparison with supervised learning, shows that the Foundation Model has the potential to reduce the gap between the maximum AUC and minimum AUC evaluations across gender and age groups. However, in a data-efficient generalization, the model increases the bias when the data amount decreases. These findings suggest that when deploying a Foundation Model in real-life scenarios with limited data, the possibility of fairness issues should be considered.
