Individually Fair Learning with One-Sided Feedback

TL;DR

This paper introduces an online learning framework that ensures individual fairness using one-sided feedback and multiple auditors, leveraging bandit algorithms to balance accuracy and fairness.

Contribution

It extends existing fairness frameworks to incorporate multiple, possibly inconsistent auditors and reduces the problem to a contextual semi-bandit setting for efficient learning.

Findings

Achieves multi-criteria no regret guarantees for accuracy and fairness.

Mitigates human biases by panel-based fairness violation detection.

Eliminates hidden outcome biases present in prior full-information models.

Abstract

We consider an online learning problem with one-sided feedback, in which the learner is able to observe the true label only for positively predicted instances. On each round, $k$ instances arrive and receive classification outcomes according to a randomized policy deployed by the learner, whose goal is to maximize accuracy while deploying individually fair policies. We first extend the framework of Bechavod et al. (2020), which relies on the existence of a human fairness auditor for detecting fairness violations, to instead incorporate feedback from dynamically-selected panels of multiple, possibly inconsistent, auditors. We then construct an efficient reduction from our problem of online learning with one-sided feedback and a panel reporting fairness violations to the contextual combinatorial semi-bandit problem (Cesa-Bianchi & Lugosi, 2009, Gy\"{o}rgy et al., 2007). Finally, we show how to leverage the guarantees of two algorithms in the contextual combinatorial semi-bandit setting: Exp2 (Bubeck et al., 2012) and the oracle-efficient Context-Semi-Bandit-FTPL (Syrgkanis et al., 2016), to provide multi-criteria no regret guarantees simultaneously for accuracy and fairness. Our results eliminate two potential sources of bias from prior work: the "hidden outcomes" that are not available to an algorithm operating in the full information setting, and human biases that might be present in any single human auditor, but can be mitigated by selecting a well chosen panel.