Bias-inducing geometries: an exactly solvable data model with fairness implications

Fuente: arXiv
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Auteurs principaux: Mannelli, Stefano Sarao, Gerace, Federica, Rostamzadeh, Negar, Saglietti, Luca
Format: Preprint
Publié: 2022
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author Mannelli, Stefano Sarao
Gerace, Federica
Rostamzadeh, Negar
Saglietti, Luca
author_facet Mannelli, Stefano Sarao
Gerace, Federica
Rostamzadeh, Negar
Saglietti, Luca
contents Machine learning (ML) may be oblivious to human bias but it is not immune to its perpetuation. Marginalisation and iniquitous group representation are often traceable in the very data used for training, and may be reflected or even enhanced by the learning models. In the present work, we aim at clarifying the role played by data geometry in the emergence of ML bias. We introduce an exactly solvable high-dimensional model of data imbalance, where parametric control over the many bias-inducing factors allows for an extensive exploration of the bias inheritance mechanism. Through the tools of statistical physics, we analytically characterise the typical properties of learning models trained in this synthetic framework and obtain exact predictions for the observables that are commonly employed for fairness assessment. Despite the simplicity of the data model, we retrace and unpack typical unfairness behaviour observed on real-world datasets. We also obtain a detailed analytical characterisation of a class of bias mitigation strategies. We first consider a basic loss-reweighing scheme, which allows for an implicit minimisation of different unfairness metrics, and quantify the incompatibilities between some existing fairness criteria. Then, we consider a novel mitigation strategy based on a matched inference approach, consisting in the introduction of coupled learning models. Our theoretical analysis of this approach shows that the coupled strategy can strike superior fairness-accuracy trade-offs.
format Preprint
id arxiv_https___arxiv_org_abs_2205_15935
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle Bias-inducing geometries: an exactly solvable data model with fairness implications
Mannelli, Stefano Sarao
Gerace, Federica
Rostamzadeh, Negar
Saglietti, Luca
Machine Learning
Disordered Systems and Neural Networks
Machine learning (ML) may be oblivious to human bias but it is not immune to its perpetuation. Marginalisation and iniquitous group representation are often traceable in the very data used for training, and may be reflected or even enhanced by the learning models. In the present work, we aim at clarifying the role played by data geometry in the emergence of ML bias. We introduce an exactly solvable high-dimensional model of data imbalance, where parametric control over the many bias-inducing factors allows for an extensive exploration of the bias inheritance mechanism. Through the tools of statistical physics, we analytically characterise the typical properties of learning models trained in this synthetic framework and obtain exact predictions for the observables that are commonly employed for fairness assessment. Despite the simplicity of the data model, we retrace and unpack typical unfairness behaviour observed on real-world datasets. We also obtain a detailed analytical characterisation of a class of bias mitigation strategies. We first consider a basic loss-reweighing scheme, which allows for an implicit minimisation of different unfairness metrics, and quantify the incompatibilities between some existing fairness criteria. Then, we consider a novel mitigation strategy based on a matched inference approach, consisting in the introduction of coupled learning models. Our theoretical analysis of this approach shows that the coupled strategy can strike superior fairness-accuracy trade-offs.
title Bias-inducing geometries: an exactly solvable data model with fairness implications
topic Machine Learning
Disordered Systems and Neural Networks
url https://arxiv.org/abs/2205.15935