想搞懂链接预测公平性指标怎么选？这篇复现研究告诉你Δ_DP会漏掉排名里的偏见，NDKL和MORAL才是真能打的。
Mattos等人2025年提出，人口统计均等（Δ_DP）无法检测链接排名中的曝光偏差。本复现研究证明，即使某些子群链接被系统排名靠后，Δ_DP仍可能显示总体均等。研究验证了排名感知的归一化KL散度（NDKL）能有效检测此类差异，并复现了后处理方法MORAL在保持效用的同时改善曝光公平性。实验覆盖合成同质性设置、分类敏感属性及多种公平性指标，结果显示MORAL在多样场景中仅以极小效用损失减少偏差。代码已开源。
Fairness in Link Prediction Beyond Demographic Parity: A Reproducibility Study
In fair ranked link prediction, demographic parity ($Δ_\mathrm{DP}$) is a common fairness metric. Yet, Mattos et al. (2025) argue that it fails to detect exposure bias because it ignores where links appear in the ranking. In this study, we reproduce this claim by showing that $Δ_\mathrm{DP}$ can indicate aggregate parity even when some subgroup-pair links are systematically ranked lower than others. The proposed rank-aware Normalized Discounted KL-divergence (NDKL), however, does detect such disparities. We also reproduce the effectiveness of MORAL, a post-processing method that improves exposure-based fairness while maintaining competitive utility. Beyond reproduction, we assess robustness using synthetic homophily settings, categorical sensitive attributes, and additional fairness and utility metrics, including subgroup-pair-adapted Attention-Weighted Rank Fairness (AWRF). Overall, our results show that exposure-based metrics uncover biases hidden by $Δ_\mathrm{DP}$ and that MORAL reduces these biases with minimal utility loss across diverse settings and datasets. We release a corrected, reproducible implementation at https://github.com/Floris93100/reproducing-MORAL.