From Parity to Preference-based Notions of Fairness in Classification

TL;DR

This paper introduces preference-based fairness notions in classification, inspired by economics, which allow for more accurate decisions than traditional parity-based fairness by focusing on group preferences over outcomes.

Contribution

It proposes a novel preference-based fairness framework, along with tractable proxies for designing classifiers that satisfy these notions, improving decision accuracy.

Findings

Preference-based fairness yields higher accuracy than parity-based fairness.

The proposed classifiers effectively incorporate group preferences.

Experiments on synthetic and real datasets validate the approach.

Abstract

The adoption of automated, data-driven decision making in an ever expanding range of applications has raised concerns about its potential unfairness towards certain social groups. In this context, a number of recent studies have focused on defining, detecting, and removing unfairness from data-driven decision systems. However, the existing notions of fairness, based on parity (equality) in treatment or outcomes for different social groups, tend to be quite stringent, limiting the overall decision making accuracy. In this paper, we draw inspiration from the fair-division and envy-freeness literature in economics and game theory and propose preference-based notions of fairness -- given the choice between various sets of decision treatments or outcomes, any group of users would collectively prefer its treatment or outcomes, regardless of the (dis)parity as compared to the other groups. Then, we introduce tractable proxies to design margin-based classifiers that satisfy these preference-based notions of fairness. Finally, we experiment with a variety of synthetic and real-world datasets and show that preference-based fairness allows for greater decision accuracy than parity-based fairness.