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Slide 2 A Very Brief Look at the Bing Ranking Algorithm Chris Burges Ofer Dekel Qiang Wu Krysta Svore Presented by Chris Burges at the MSR Faculty Summit, July 18, 2011 (narration begins on next slide) Slide 3 Slide 4 How LambdaRank is Trained Query: 107.7 the end URLRatingModel Score http://www.1077theend.com Perfect0.13 http://en.wikipedia.org/wiki/10 7.7_The_End Good0.21 http://www.myspace.com/107 7theend Good0.19 http://en.wikipedia.org/wiki/T he_End Fair0.01 http://www.thewolf.co.uk/ Bad0.23 URLRatingModel ScoreForces http://www.thewolf.co.uk/ Bad0.23 http://en.wikipedia.org/wiki/10 7.7_The_End Good0.21 http://www.myspace.com/107 7theend Good0.19 http://www.1077theend.com Perfect0.13 http://en.wikipedia.org/wiki/T he_End Fair0.01 Slide 5 Building an ensemble of regression trees RatingUrlScoreForce Badhttp://www.thewolf.co.uk/ 0.23-0.53 Goodhttp://en.wikipedia.org/wiki/107.7_The_End 0.21-0.04 Goodhttp://www.myspace.com/1077theend 0.19 0.04 Perfecthttp://www.1077theend.com 0.13 0.55 Fairhttp://en.wikipedia.org/wiki/The_End 0.01-0.02 RatingUrlScoreForce Goodhttp://en.wikipedia.org/wiki/107.7_The_End 0.21-0.04 Badhttp://www.thewolf.co.uk/ 0.20-0.47 Goodhttp://www.myspace.com/1077theend 0.19 0.04 Perfecthttp://www.1077theend.com 0.16 0.48 Fairhttp://en.wikipedia.org/wiki/The_End 0.01-0.02 RatingUrlScoreForce Goodhttp://en.wikipedia.org/wiki/107.7_The_End 0.20-0.09 Perfecthttp://www.1077theend.com 0.19 0.37 Goodhttp://www.myspace.com/1077theend 0.19 0.04 Badhttp://www.thewolf.co.uk/ 0.17-0.35 Fairhttp://en.wikipedia.org/wiki/The_End 0.01 0.10 + + Slide 6 How is a split computed? RatingUrlBM25FCount of query in body Anchor text matches query Function(click frequency) Badhttp://www.thewolf.co.uk/553701300 Goodhttp://en.wikipedia.org/wiki/107.7_The_End8100013620 Goodhttp://www.myspace.com/1077theend80981000 Perfecthttp://www.1077theend.com810236025286251 Fairhttp://en.wikipedia.org/wiki/The_End8098415620490 L R Slide 7 FastRank: Algorithms Engineering We only need one linear scan of the data (in a given node) to compute this. Thresholds Forces Counts Slide 8 Thanks!