New Leader In Netflix Prize Race With One Day To Go

brajesh writes "The Netflix Prize, an algorithm competition to improve the Netflix Cinematch recommendation system by more than 10%, has a new leader — The Ensemble — just one day before the competition ends. The 30-day race to the end was kicked off after BellKor's Pragmatic Chaos submitted the first entry to break the 10% barrier, with the results showing a 10.08% improvement. The Ensemble, made up of three teams who chose to join forces ('Grand Prize Team,' 'Opera Solutions' and 'Vandelay United), has managed to overtake BellKor with a score of 10.09% — an improvement of .01% over the former leaders. From the article on Techcrunch: 'The competition will end [today], so teams still have a little bit of time left to make their last-second submissions, but things are looking good for The Ensemble. This has to be absolutely brutal for team BellKor.'"

I used to be very elitist about my reading

[BadAnalogyGuy]

Back when I first began using Amazon.com, I never bought a book based on the recommended items. I felt the recommendations were trite, ill-advised, and typically only peripherally related to the item I was buying.

Then the recommendations got better. Much better. I started to find myself buying things right out of the recommended section, and the product combination deals also became very tempting.

If Netflix can turn their recommendation engine into something similar, they will be sitting on a goldmine. As they say, people hate get sold to but they love buying.

should've "gamed" it

[petes_PoV]

rather than declaring your best result early, the Belkor team should have employed a bit of strategy and only declared a lesser result (if any). That would give the other teams something to aim at, without giving away their best results. These would be held back right up until the last minute and then submitted, so that other teams would not have time to make any further improvements (in fact, maybe this IS what they're doing). It's been a successful bidding strategy on eBay for years, so why wouldn't it translate into other competitive areas too?

Re:Why now?

[caffeinemessiah]

Why not wait another day before submitting the improvement? All they did now was giving the other team one day to respond, and if they succeed, I doubt they will be able to submit yet another improvement. So why not simply wait until an hour or so before the deadline, or am I missing something about the rules, e.g. any submitted improvements prolong the deadline by one day?

For the grand prize, there was a final 30-day countdown from the time the first entry that achieved greater than 10% was received, which was a month ago. So it seems like this will indeed come down to an ebay-like sniping situation in the last few hours.

I wouldn't feel too sorry for BellKor/KorBell though -- they've got many, many best paper awards at conferences and a huge degree of publicity out of the whole endeavor. In fact, in KDD 2009, they detailed most of the methods that most likely got them to the top -- i.e. they incorporated the fact that tastes and preferences drift over time. Simple, in retrospect of course. If you have an ACM subscription, you can read the 2009 paper here [acm.org].

Plus, since they work for AT&T/Yahoo Research, I remember Yehuda Koren stating that the money wouldn't have gone to them anyway -- possibly a large bonus, but I think they're entitled to that anyway. So I wouldn't feel too sorry for them.

Any winner at all?

[Fnord666]

My question is whether there will be any winner at all other than netflix? One of the rules for the competition was that you could not form multiple teams. This was to prevent people from gaining multiple submissions per day. Otherwise a five person group could create 30 teams and thus be able to submit 30 attempts per day. I believe both teams that have exceeded the 10% threshold and thus are eligible for the grand prize are composed of members from other teams and could be disqualified.

Be afraid.... be very afraid...

[Baldrson]

It's interesting that the fearmongering of the prior /. post about AI got hundreds of responses but this /. post, which is far more relevant to real AI, has gotten less than a hundred responses thus far. Anyway, congratulations to Netfilx for doing the right thing for their business in response to The Hutter Prize.