Social Foundations of Computation Conference Paper 2024

Fairness Rising from the Ranks: HITS and PageRank on Homophilic Networks

In this paper, we investigate the conditions under which link analysis algorithms prevent minority groups from reaching high-ranking slots. We find that the most common link-based algorithms using centrality metrics, such as PageRank and HITS, can reproduce and even amplify bias against minority groups in networks. Yet, their behavior differs: on the one hand, we empirically show that PageRank mirrors the degree distribution for most of the ranking positions and it can equalize representation of minorities among the top-ranked nodes; on the other hand, we find that HITS amplifies pre-existing bias in homophilic networks through a novel theoretical analysis, supported by empirical results. We find the root cause of bias amplification in HITS to be the level of homophily present in the network, modeled through an evolving network model with two communities. We illustrate our theoretical analysis on both synthetic and real datasets and we present directions for future work.

Author(s): Stoica, Ana-Andreea and Litvak, Nelly and Chaintreau, Augustin
Book Title: Proceedings of the Association for Computing Machinery (ACM) Web Conference 2024
Year: 2024
Month: May
Publisher: ACM
Bibtex Type: Conference Paper (inproceedings)
Event Name: The 2024 ACM Web Conference
State: Published
URL: https://dl.acm.org/doi/10.1145/3589334.3645609
Electronic Archiving: grant_archive
Links:

BibTex

@inproceedings{stoica2024fairness,
  title = {Fairness Rising from the Ranks: HITS and PageRank on Homophilic Networks},
  booktitle = {Proceedings of the Association for Computing Machinery (ACM) Web Conference 2024},
  abstract = {In this paper, we investigate the conditions under which link analysis algorithms prevent minority groups from reaching high-ranking slots. We find that the most common link-based algorithms using centrality metrics, such as PageRank and HITS, can reproduce and even amplify bias against minority groups in networks. Yet, their behavior differs: on the one hand, we empirically show that PageRank mirrors the degree distribution for most of the ranking positions and it can equalize representation of minorities among the top-ranked nodes; on the other hand, we find that HITS amplifies pre-existing bias in homophilic networks through a novel theoretical analysis, supported by empirical results. We find the root cause of bias amplification in HITS to be the level of homophily present in the network, modeled through an evolving network model with two communities. We illustrate our theoretical analysis on both synthetic and real datasets and we present directions for future work.},
  publisher = {ACM},
  month = may,
  year = {2024},
  slug = {stoica2024fairness},
  author = {Stoica, Ana-Andreea and Litvak, Nelly and Chaintreau, Augustin},
  url = {https://dl.acm.org/doi/10.1145/3589334.3645609},
  month_numeric = {5}
}