Knowledge Graph-based recommender systems naturally produce explainable recommendations, by showing the reasoning paths in the knowledge graph (KG) that were followed to select the recommended items. One can define metrics that assess the quality of the explanation paths in terms of recency, popularity, and diversity. Combining in- and post-processing approaches to optimize for both recommendation …
Day: August 2, 2023
Enabling Reproducibility in Group Recommender Systems
Group recommender systems produce suggestions in contexts in which more than one person is involved in the recommendation process. They present additional tasks w.r.t. those for single users, such as the identification of the groups, or their modeling. While this clearly amplifies the possible reproducibility issues, to date, no framework to benchmark group recommender systems …
Fair performance-based user recommendation in eCoaching systems
When ranking sportspeople so that a coach can assist those who are in need, users of different genders might be affected by disparate exposure, meaning that the users in the minority group are systematically ranked in lower positions. A re-ranking can help mitigate disparities, without affecting recommendation quality. In a study, published by the User …
Do Graph Neural Networks Build Fair User Models? Assessing Disparate Impact and Mistreatment in Behavioural User Profiling
User profiling approaches that model the interaction between users and items (behavioral user profiling) via Graph Neural Networks (GNNs) are unfair toward certain demographic groups. In a CIKM 2022 study, conducted with Erasmo Purificato and Ernesto William De Luca, we perform a beyond-accuracy analysis of the state-of-the-art approaches to assess the presence of disparate impact …
Robust reputation independence in ranking systems for multiple sensitive attributes
Ranking systems that account for the reputation of the users can be biased towards different demographic groups, especially when considering multiple sensitive attributes (e.g., gender and age). Providing guarantees of reputation independence can lead to unbiased and effective rankings. Moreover, these rankings are also robust to attacks. In a study, published by the Machine Learning …