Fair Kernel Learning

TL;DR

This paper introduces novel kernel-based fair regression and dimensionality reduction methods that incorporate multiple sensitive variables into the fairness objective, applicable to nonlinear problems, simplifying solution computation.

Contribution

It presents a unified kernel-based framework for fair regression and dimensionality reduction that handles multiple sensitive features and nonlinearities efficiently.

Findings

Effective in toy examples demonstrating fairness improvements.

Successful application to real-world income prediction datasets.

Simplifies the computation of fair solutions via matrix inversions or eigenvalue problems.

Abstract

New social and economic activities massively exploit big data and machine learning algorithms to do inference on people's lives. Applications include automatic curricula evaluation, wage determination, and risk assessment for credits and loans. Recently, many governments and institutions have raised concerns about the lack of fairness, equity and ethics in machine learning to treat these problems. It has been shown that not including sensitive features that bias fairness, such as gender or race, is not enough to mitigate the discrimination when other related features are included. Instead, including fairness in the objective function has been shown to be more efficient. We present novel fair regression and dimensionality reduction methods built on a previously proposed fair classification framework. Both methods rely on using the Hilbert Schmidt independence criterion as the fairness term. Unlike previous approaches, this allows us to simplify the problem and to use multiple sensitive variables simultaneously. Replacing the linear formulation by kernel functions allows the methods to deal with nonlinear problems. For both linear and nonlinear formulations the solution reduces to solving simple matrix inversions or generalized eigenvalue problems. This simplifies the evaluation of the solutions for different trade-off values between the predictive error and fairness terms. We illustrate the usefulness of the proposed methods in toy examples, and evaluate their performance on real world datasets to predict income using gender and/or race discrimination as sensitive variables, and contraceptive method prediction under demographic and socio-economic sensitive descriptors.