  In this work, we present Fairness Aware Counterfactuals for Subgroups
(FACTS), a framework for auditing subgroup fairness through counterfactual
explanations. We start with revisiting (and generalizing) existing notions and
introducing new, more refined notions of subgroup fairness. We aim to (a)
formulate different aspects of the difficulty of individuals in certain
subgroups to achieve recourse, i.e. receive the desired outcome, either at the
micro level, considering members of the subgroup individually, or at the macro
level, considering the subgroup as a whole, and (b) introduce notions of
subgroup fairness that are robust, if not totally oblivious, to the cost of
achieving recourse. We accompany these notions with an efficient,
model-agnostic, highly parameterizable, and explainable framework for
evaluating subgroup fairness. We demonstrate the advantages, the wide
applicability, and the efficiency of our approach through a thorough
experimental evaluation of different benchmark datasets.
