BellKor's Pragmatic Chaos

BellKor's Pragmatic Chaos is the winner of the $1 Million Netflix Prize!!!!!

Grand Prize Big Check!
source: Getty Images

On September 21, 2009 BellKor's Pragmatic Chaos was announced as the winner of the $1M Netflix Prize at a ceremony in New York City. 

Details on the event from the NYTimes Bits Blog, Fortune Magazine, and Business Week

AT&T will be donating its share of the prize to educational charities.

Nice articles on the implications of the Netflix Prize from Wired and Slate.

Analysis of combining Ensemble and BPC models from The Ensemble Blog.

AT&T Tech Channel video interview highlighting Bell and Volinsky.

Old News:
         September 10There are rumors popping up that Netflix will be announcing the official winner of the Netflix Prize in a ceremony in New York City on September 21.  

         September 8:  Check out our colleague Yifan Hu's cool interactive maps on the Netflix movie database.

         September 4: Bob Bell featured in a kinda weird article, originally in the Washington Post: "Movie tips from your robot overlords "

        August 5: Bob Bell was interviewed for the NPR show "On The Media":  Getting to Know You      

         August 5: Team BellKor's article on matrix factorization methods in in the new edition of IEEE Computer: Matrix Factorization Techniques for Recommender

        July 30
:  The two top teams have posted about the suspense of the  last hours of the competition.  Our own Pragmatic Theory gives our version, while our colleagues in The Ensemble's Lester Mackey reports on the dramatic final minutes.
        July 29:   Gavin Potter, the infamous "guy in a garage" gives his views on what we have learned from the Netflix Prize on his blog.  His views are spot-on: giving credit to Netflix, Simon Funk, and all of the top competitors for a "spirit of openness and co-operation". 

        July 28:  A nice article by Steve Lohr in the New York Times sums up the state of the competition:  Netflix Competitors Learn the Power of Teamwork.

        July 28:  Lots of great blogosphere coverage of the fantastic conclusion to the prize.  It is fun to read the comments to these blog posts...some have interesting insights, others not so much.:

                       TechCrunch: The Netflix Prize Comes To A Buzzer-Beater, Nailbiting Finish
                       This Is The Green Room: Photo-finish, The Netflix Prize
                       Mashable: Netflix Prize: And the $1 Million Winner Is…?
                       NYT Bits Blog:  Netflix Challenge Ends, But Winner Is In Doubt - Bits Blog ...
                       Industry Standard:  Netflix Service May Get Smarter
                       Techdirt: What The Netflix Prize Tells Us About Innovation, Collaboration, Info Sharing And Game Theory
        July 26: 3:42 PM EDT:  We receive The Email from Netflix!  We are the current "top contender" for the Grand Prize!  

        July 26:  A hectic 24 hours!  After frantically searching for some last minute 'secret sauce', we made our last submission just an hour before the contest closed.  Our improvement of one-hundredth of a percent was matched shortly afterward by The Ensemble, who remain ahead of us on the public leaderboard...

        July 25:  A coalition of our top competitors formed to create The Ensemble, and became the second team to pass the 10% barrier, leapfrogging us into first place on the Quiz Set.  This created quite a stir in the blogosphere!  Congratulations to our fellow competitors.
        July 24: A few quotes from our team in the excellent article about the Netflix Prize in Communications of the ACM:  Just For You.

        July 8:  Yehuda was highlighted on the front page of the CACM web page, congtratulating him on the Netflix Prize work and his Best Paper article at KDD.   Here is the article.   Hooray for Yehuda!

       July 8:
More exciting maneuverings on the leaderboard as new coalitions have been created, and are challenging the 10% mark.   We've still got a good lead, but perhaps less comfy.

       July 7: 
Article in Business week about the competition.  Apparently Netflix plans some 'pomp and circumstance' for the winner. Hmmm...

        June 30:
  MediaUnbound is running a series on the Netflix Prize in the final 30 days called Countdown to 10%.

       June 30:  Coverage on John Langford's Machine Learning Blog. Of note is the first commenter, who points out his/her views on the ML contributions of the contest.
       June 29:  There is a fascinating story unfolding, as other teams attempt to collaborate to challenge our current score before the end of the 30 day "last call".  At least three groups are gathering up colleagues on the leaderboard to see where the benefits lie.  This is great!  It is this collaborative spirit and friendly competition that has made this endeavor so enjoyable for 2.5 years.  See you at the finish line!

June 29:  Lots of news and blog coverage: NYTimes Bits Blog;; Mashable; NewScientist; Slashdot; Reddit;Associated Press
       June 29:  Checking the server logs: About 60K hits on this web page over the weekend! This chart shows where the traffic came from by plotting the referrers in different colors.  By far, the largest referrer to our page was Looking at the plot minute-by-minute shows an interesting spike - which seems to be totally due to traffic from stumbleupon.  Go figure.  Also, a few hundred Tweets this weekend about the prize.

       June 26, 2009:  Pragmatic Theory have a fun blog post about our new team name.

       June 26, 2009:  Today our team submitted our solution to the Netflix Prize, resulting in a score of .8558, which corresponds to an improvement over Netflix Cinematch algorithm of 10.05%.  This is the first submission in the competition to break the 10% barrier and sets off a 30 day period where all competitors are invited to submit their best and final solutions.



             BellKor's Pragmatic Chaos is:


Bob Bell and Chris Volinsky, members of the Statistics Research Department at AT&T Research, and winner of the 2007 and 2008 Progress Prizes as members of team BellKor.

commendo Andreas Toscher and Michael Jahrer,  machine learning researchers and founders of commendo research and consulting in Austria.  They won the 2008 Progress Prize as  members of the team Big Chaos.

prag Electrical engineer Martin Piotte and software engineer Martin Chabbert of Montreal, and  founders of Pragmatic Theory.

yahoo Yehuda Koren, Senior Research Scientist at Yahoo! Research Israel, and winner of the 2007 and 2008
Progress Prizes as a member of team BellKor.