We study the task of node classification for graph neural networks (GNNs) and establish a connection between group fairness, as measured by statistical parity and equal opportunity, and local assortativity, i.e., the tendency of linked nodes to have similar attributes. Such assortativity is often induced by homophily, the tendency for nodes of similar properties to connect. Homophily can be common in social networks where systemic factors have forced individuals into communities which share a sensitive attribute. Through synthetic graphs, we study the interplay between locally occurring homophily and fair predictions, finding that not all node neighborhoods are equal in this respect -- neighborhoods dominated by one category of a sensitive attribute often struggle to obtain fair treatment, especially in the case of diverging local class and sensitive attribute homophily. After determining that a relationship between local homophily and fairness exists, we investigate if the issue of unfairness can be associated to the design of the applied GNN model. We show that by adopting heterophilous GNN designs capable of handling disassortative group labels, group fairness in locally heterophilous neighborhoods can be improved by up to 25% over homophilous designs in real and synthetic datasets.

本文研究了节点分类的任务，并建立了群体公平性（以统计平衡和平等机会方式衡量）与局部同配性之间的联系，即链接节点具有相似属性的趋势，在社交网络中，这种同配性通常是由于同质性引起的，而同质性可以迫使个人进入共享敏感属性的社区；通过合成图，我们研究了本地同质性和公平预测之间的相互作用，发现并非所有节点邻域在这方面都是平等的。本文还研究了是否可以将不公平问题与应用GNN模型的设计相关联，我们发现采用能够处理非同配组标签的异质性GNN设计可以在真实和合成数据集中将局部异质性邻域的群体公平性提高高达25％，优于同质性设计。

图神经网络在异质临近度下的公平性