---
title: "Proxy variable"
description: "A feature that carries the information of a protected characteristic, such as postcode for ethnicity, so that a model can discriminate without using the attribute itself."
canonical: https://aigovernanceengineer.com/glossary/proxy-variable
author: "Jorge García Aibar"
license: "CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/)"
doi: https://doi.org/10.5281/zenodo.22956197
version: "0.5.0"
updated: 2026-09-24
---

# Proxy variable

A feature that carries the information of a protected characteristic, such as postcode for ethnicity, so that a model can discriminate without using the attribute itself. Proxy tests look for features that predict the protected attribute [1].

- Developed in: [ch. 16, Protected characteristics, proxies and the data you need to test](https://aigovernanceengineer.com/bok/fairness-and-explainability#protected-characteristics-proxies-and-the-data-you-need-to-test)
- Chapters: [ch. 16, Fairness & XAI](https://aigovernanceengineer.com/bok/fairness-and-explainability) · [ch. 20, Existing Law](https://aigovernanceengineer.com/bok/existing-law)
- Contrast with: [Proxy label](https://aigovernanceengineer.com/glossary/proxy-label)
- In the glossary chapter: https://aigovernanceengineer.com/bok/glossary#t-proxy-variable

## Sources

[1] "Dissecting racial bias in an algorithm used to manage the health of populations" (Obermeyer, Powers, Vogeli and Mullainathan; Science 366(6464):447-453; cost as a proxy for need). Science. 2019-10-25. https://doi.org/10.1126/science.aax2342 (verified: primary)