In episode 19 of Recsperts, we welcome Himan Abdollahpouri who is an Applied Research Scientist for Personalization & Machine Learning at Spotify. We discuss the role of popularity bias in recommender systems which was the dissertation topic of Himan. We talk about multi-objective and multi-stakeholder recommender systems as well as the challenges of music and podcast streaming personalization at Spotify.

In our interview, Himan walks us through popularity bias as the main cause of unfair recommendations for multiple stakeholders. We discuss the consumer- and provider-side implications and how to evaluate popularity bias. Not the sheer existence of popularity bias is the major problem, but its propagation in various collaborative filtering algorithms. But we also learn how to counteract by debiasing the data, the model itself, or it's output. We also hear more about the relationship between multi-objective and multi-stakeholder recommender systems.

At the end of the episode, Himan also shares the influence of popularity bias in music and podcast streaming at Spotify as well as how calibration helps to better cater content to users' preferences.

Enjoy this enriching episode of RECSPERTS - Recommender Systems Experts.
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(00:00) - Introduction
(04:43) - About Himan Abdollahpouri
(15:23) - What is Popularity Bias and why is it important?
(25:05) - Effect of Popularity Bias in Collaborative Filtering
(30:30) - Individual Sensitivity towards Popularity
(36:25) - Introduction to Bias Mitigation
(53:16) - Content for Bias Mitigation
(56:53) - Evaluating Popularity Bias
(01:05:01) - Popularity Bias in Music and Podcast Streaming
(01:08:04) - Multi-Objective Recommender Systems
(01:16:13) - Multi-Stakeholder Recommender Systems
(01:18:38) - Recommendation Challenges at Spotify
(01:35:16) - Closing Remarks

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