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AI Governance Glossary
Governance Concept

What Is Fairness Metric?

Fairness Metric is a quantitative measure used to evaluate whether an AI system produces equitable outcomes across different demographic or protected groups.

Definition

Fairness Metrica quantitative measure used to evaluate whether an AI system produces equitable outcomes across different demographic or protected groups.

Common fairness metrics include: demographic parity (equal positive prediction rate across groups), equalised odds (equal true positive and false positive rates), and individual fairness (similar individuals receive similar outputs). A fundamental challenge — proven mathematically by the Impossibility Theorem (Chouldechova, 2017; Kleinberg et al., 2016) — is that these metrics cannot all be satisfied simultaneously except in trivial cases. This means fairness is a values question, not a pure technical problem: organisations must explicitly choose which fairness definition to optimise for, and document the choice.

Source: Chouldechova (2017); Kleinberg et al. (2016); NYC LL144 audit requirements

Plain-language explanation

Common fairness metrics include: demographic parity (equal positive prediction rate across groups), equalised odds (equal true positive and false positive rates), and individual fairness (similar individuals receive similar outputs). A fundamental challenge — proven mathematically by the Impossibility Theorem (Chouldechova, 2017; Kleinberg et al., 2016) — is that these metrics cannot all be satisfied simultaneously except in trivial cases. This means fairness is a values question, not a pure technical problem: organisations must explicitly choose which fairness definition to optimise for, and document the choice.

Primary source: Chouldechova (2017); Kleinberg et al. (2016); NYC LL144 audit requirements

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