What Is Proxy Discrimination?

Proxy Discrimination — discrimination that arises when a model relies on a neutral-looking variable that correlates strongly with a protected characteristic.

Removing protected attributes such as race or sex from a model does not remove bias if other features — postcode, school, shopping patterns — stand in for them. Proxy discrimination is why fairness work looks at outcomes and correlations, not just whether a protected field was used, and why "we don't collect that data" is not a defence against biased results.

Source: Fairness and anti-discrimination literature