Netflix Prize contest closes; Ensemble wins

July 26th, 2009

Netflix has announced that the Netflix Prize contest is now closed. Presumably, The Ensemble is the winner, subject to final qualification.

“We are delighted to report that, after almost three years and more than 43,000 entries from over 5,100 teams in over 185 countries, the Netflix Prize Contest stopped accepting entries on 2009-07-26 18:42:37 UTC. The closing of the contest is in accordance with the Rules — thirty (30) days after a submitted prediction set achieved the Grand Prize qualifying RMSE on the quiz subset.

Qualified entries will be evaluated as described in the Rules. We look forward to awarding the Grand Prize, which we expect to announce in a few weeks. However if a Grand Prize cannot be awarded because no submission can be verified by the judges, the Contest will reopen. We will make an announcement on the Forum after the Contest judges reach a decision.”

So what’s left for the judges to do. The rules say that “a panel of senior Netflix engineers and qualified independent judges” need to “ensure that the provided algorithm description and source code could reasonably have generated the prediction sets submitted”. To do this, the candidate winner must produce the algorithm along with a description of who it works. And, of course, before receiving the prize the winner has to grant Netflix

“an irrevocable, royalty free, fully paid up, worldwide non-exclusive license under the Participants’ copyrights, patents or other intellectual property rights in the winning algorithm (“Winning Algorithm”) to reproduce, distribute, display, and create derivative works from the Winning Algorithm and also to make, have made, use, sell, offer for sale, and import products that would otherwise infringe the Winning Algorithm.”

The Netflix Prize was a great idea and generated a lot of interest around the world. It’s been good for the field of AI and its machine learning sub-field, especially. Congratulations to the Ensemble team and condolences to BellKor’s Pragmatic Chaos. I wish there could have been two winners.

UPDATE 2/27: Wait! The winner is still in doubt.