Demographic Parity

Demographic parity is a group fairness criterion requiring the rate of a positive prediction or decision to be the same across protected groups. It focuses on outcomes rather than whether the underlying labels were positive or negative. The measure can reveal unequal allocation, but satisfying it may conflict with accuracy, calibration, equalized odds, or legal and policy goals when base rates differ. It also depends on how groups and outcomes are defined, and equal aggregate rates can conceal intersectional or individual harms. Demographic parity should therefore be treated as one diagnostic within a broader assessment that includes context, data history, error costs, affected communities, and possible remedies.