IFFair: Influence Function-driven Sample Reweighting for Fair Classification

Because machine learning has significantly improved efficiency and convenience in the society, it's increasingly us ed to assist or replace human decision-making. However, the data-based pa ttern makes related algorithms learn and even exacerbate potential bia s in samples, resulting in discriminatory decisions against certain unp rivileged groups, depriving them of the rights to equal treatment, thus damagi ng the social well-being and hindering the development of related applic ations. Therefore, we propose a pre-processing method IFFair based on the influence function. Compared with other fairness optimization appro aches, IFFair only uses the influence disparity of training samples on diffe rent groups as a guidance to dynamically adjust the sample weights durin g training without modifying the network structure, data features and decision boundaries. To evaluate the validity of IFFair, we conduct e xperiments on multiple real-world datasets and metrics. The experimenta l results show that our approach mitigates bias of multiple accepted metri cs in the classification setting, including demographic parity, equaliz ed odds, equality of opportunity and error rate parity without conflicts. It al so demonstrates that IFFair achieves better trade-off between multi ple utility and fairness metrics compared with previous pre-processing me thods.