Equalised Odds is not Equal Individual Odds: Post-processing for Group and Individual Fairness

arXiv:2304.09779v3 Announce Type: replace
Abstract: Group fairness is achieved by equalising prediction distributions between protected sub-populations; individual fairness requires treating similar individuals alike. These two objectives, however, are incompatible when a scoring model is calibrated through discontinuous probability functions, where individuals can be randomly assigned an outcome determined by a fixed probability. This procedure may provide two similar individuals from the same protected group with classification odds that are disparately different -- a clear violation of individual fairness. Assigning unique …

abstract arxiv cs.cy cs.lg equal fairness functions however math.oc math.pr post-processing prediction probability processing scoring through type