Simpson's Paradox in Recommender Fairness: Reconciling differences between per-user and aggregated evaluations. (arXiv:2210.07755v1 [cs.IR])

There has been a flurry of research in recent years on notions of fairness in
ranking and recommender systems, particularly on how to evaluate if a
recommender allocates exposure equally across groups of relevant items (also
known as provider fairness). While this research has laid an important
foundation, it gave rise to different approaches depending on whether relevant
items are compared per-user/per-query or aggregated across users. Despite both
being established and intuitive, we discover that these two notions can lead …

arxiv fairness paradox