The Impact of Differential Privacy on Recommendation Accuracy and Popularity Bias

Fuente: arXiv
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Main Authors: Müllner, Peter, Lex, Elisabeth, Schedl, Markus, Kowald, Dominik
Format: Preprint
Published: 2024
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author Müllner, Peter
Lex, Elisabeth
Schedl, Markus
Kowald, Dominik
author_facet Müllner, Peter
Lex, Elisabeth
Schedl, Markus
Kowald, Dominik
contents Collaborative filtering-based recommender systems leverage vast amounts of behavioral user data, which poses severe privacy risks. Thus, often, random noise is added to the data to ensure Differential Privacy (DP). However, to date, it is not well understood, in which ways this impacts personalized recommendations. In this work, we study how DP impacts recommendation accuracy and popularity bias, when applied to the training data of state-of-the-art recommendation models. Our findings are three-fold: First, we find that nearly all users' recommendations change when DP is applied. Second, recommendation accuracy drops substantially while recommended item popularity experiences a sharp increase, suggesting that popularity bias worsens. Third, we find that DP exacerbates popularity bias more severely for users who prefer unpopular items than for users that prefer popular items.
format Preprint
id arxiv_https___arxiv_org_abs_2401_03883
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle The Impact of Differential Privacy on Recommendation Accuracy and Popularity Bias
Müllner, Peter
Lex, Elisabeth
Schedl, Markus
Kowald, Dominik
Information Retrieval
Collaborative filtering-based recommender systems leverage vast amounts of behavioral user data, which poses severe privacy risks. Thus, often, random noise is added to the data to ensure Differential Privacy (DP). However, to date, it is not well understood, in which ways this impacts personalized recommendations. In this work, we study how DP impacts recommendation accuracy and popularity bias, when applied to the training data of state-of-the-art recommendation models. Our findings are three-fold: First, we find that nearly all users' recommendations change when DP is applied. Second, recommendation accuracy drops substantially while recommended item popularity experiences a sharp increase, suggesting that popularity bias worsens. Third, we find that DP exacerbates popularity bias more severely for users who prefer unpopular items than for users that prefer popular items.
title The Impact of Differential Privacy on Recommendation Accuracy and Popularity Bias
topic Information Retrieval
url https://arxiv.org/abs/2401.03883