Debiasing Recommendation with Personal Popularity
Keywords: recommendation, item popularity, causal inference.
TL;DR: We propose a personal popularity-aware method based on causal inference to handle popularity bias in recommendation.
Abstract: Global popularity (GP) bias is the phenomenon that popular items are recommended much more frequently than they should be, which goes against the goal of providing personalized recommendations and harms user experience and recommendation accuracy. Many methods have been proposed to reduce GP bias but they fail to notice the fundamental problem of GP, i.e., it considers popularity from a \textit{global} perspective of \textit{all users} and uses a single set of popular items, and thus cannot capture the interests of individual users. As such, we propose a user-aware version of item popularity named \textit{personal popularity} (PP), which identifies different popular items for each user by considering the users that share similar interests. As PP models the preferences of individual users, it naturally helps to produce personalized recommendations and mitigate GP bias. To integrate PP into recommendation, we design a general \textit{personal popularity aware counterfactual} (PPAC) framework, which adapts easily to existing recommendation models. In particular, PPAC recognizes that PP and GP have both direct and indirect effects on recommendations and controls direct effects with counterfactual inference techniques for unbiased recommendations. Experimental results show that PPAC consistently outperforms SOTA debiasing methods across different datasets and base models, and the improvement in NDCG is up to 61.9\%. All codes and datasets are available at https://anonymous.4open.science/r/Pop-4760/.
Track: User Modeling and Recommendation
Submission Guidelines Scope: Yes
Submission Guidelines Blind: Yes
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Student Author: Yes
Submission Number: 610
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