#20: Practical Bandits and Travel Recommendations with Bram van den Akker

In episode 20 of Recsperts, we welcome Bram van den Akker, Senior Machine Learning Scientist at Booking.com. Bram's work focuses on bandit algorithms and counterfactual learning. He was one of the creators of the Practical Bandits tutorial at the World Wide Web conference. We talk about the role of bandit feedback in decision making systems and in specific for recommendations in the travel industry.In our interview, Bram elaborates on bandit feedback and how it is used in practice. We discuss off-policy- and on-policy-bandits, and we learn that counterfactual evaluation is right for selecting the best model candidates for downstream A/B-testing, but not a replacement. We hear more about the practical challenges of bandit feedback, for example the difference between model scores and propensities, the role of stochasticity or the nitty-gritty details of reward signals. Bram also shares with us the challenges of recommendations in the travel domain, where he points out the sparsity of signals or the feedback delay.At the end of the episode, we can both agree on a good example for a clickbait-heavy news service in our phones. Enjoy this enriching episode of RECSPERTS - Recommender Systems Experts.Don't forget to follow the podcast and please leave a review(00:00) - Introduction (02:58) - About Bram van den Akker (09:16) - Motivation for Practical Bandits Tutorial (16:53) - Specifics and Challenges of Travel Recommendations (26:19) - Role of Bandit Feedback in Practice (49:13) - Motivation for Bandit Feedback (01:00:54) - Practical Start for Counterfactual Evaluation (01:06:33) - Role of Business Rules (01:11:26) - better cut this section coherently (01:17:48) - Rewards and More (01:32:45) - Closing Remarks Links from the Episode:Bram van den Akker on LinkedInPractical Bandits: An Industry Perspective (Website)Practical Bandits: An Industry Perspective (Recording)Tutorial at The Web Conference 2020: Unbiased Learning to Rank: Counterfactual and Online ApproachesTutorial at RecSys 2021: Counterfactual Learning and Evaluation for Recommender Systems: Foundations, Implementations, and Recent AdvancesGitHub: Open Bandit PipelinePapers:van den Akker et al. (2023): Practical Bandits: An Industry Perspectivevan den Akker et al. (2022): Extending Open Bandit Pipeline to Simulate Industry Challengesvan den Akker et al. (2019): ViTOR: Learning to Rank Webpages Based on Visual FeaturesGeneral Links:Follow me on LinkedInFollow me on XSend me your comments, questions and suggestions to marcel.kurovski@gmail.comRecsperts Website

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Recommender Systems are the most challenging, powerful and ubiquitous area of machine learning and artificial intelligence. This podcast hosts the experts in recommender systems research and application. From understanding what users really want to driving large-scale content discovery - from delivering personalized online experiences to catering to multi-stakeholder goals. Guests from industry and academia share how they tackle these and many more challenges. With Recsperts coming from universities all around the globe or from various industries like streaming, ecommerce, news, or social media, this podcast provides depth and insights. We go far beyond your 101 on RecSys and the shallowness of another matrix factorization based rating prediction blogpost! The motto is: be relevant or become irrelevant! Expect a brand-new interview each month and follow Recsperts on your favorite podcast player.