Posts Tagged ‘contest’

It’s Official: “BellKor’s Pragmatic Chaos” Team Wins Netflix Prize

September 21st, 2009

Netflix_header_prize2009

Today Netflix Corp. awarded its long-awaited $1M Grand Prize to team “BellKor’s Pragmatic Chaos,” which consisted of Bob Bell, Martin Chabbert, Michael Jahrer, Yehuda Koren, Martin Piotte, Andreas Töscher and Chris Volinsky.

The 3-year crowdsourcing contest motivated self-forming, unpaid volunteer teams to compete for one $1 million dollar prize by creating  an algorithm which substantially improved by at least 10% the accuracy of Cinematch’s prediction about how much someone is going to enjoy a movie based on their movie preferences.

As announced by Netflix Corp:

The winning team is comprised of software and electrical engineers, statisticians and machine learning researchers from Austria, Canada, Israel and the United States. All seven team members – Bob Bell, Martin Chabbert, Michael Jahrer, Yehuda Koren, Martin Piotte, Andreas Toscher and Chris Volinsky – attended the awards ceremony. It was the first time all seven had met one another in person. How the $1 million is split is to be determined by the team.

And, from the Netflix Prize site:

It is our great honor to announce the $1M Grand Prize winner of the Netflix Prize contest as team BellKor’s Pragmatic Chaos for their verified submission on July 26, 2009 at 18:18:28 UTC, achieving the winning RMSE of 0.8567 on the test subset.  This represents a 10.06% improvement over Cinematch’s score on the test subset at the start of the contest. We congratulate the team of Bob Bell, Martin Chabbert, Michael Jahrer, Yehuda Koren, Martin Piotte, Andreas Töscher and Chris Volinsky for their superb work advancing and integrating many significant techniques to achieve this result.

The Prize was awarded in a ceremony in New York City on September 21st, 2009. We will post a video on this forum of the presentation the team delivered about their Prize algorithm. In accord with the Rules the winning team has prepared a system description consisting of three papers, which we both make public below.

Team BellKor’s Pragmatic Chaos edged out team The Ensemble with the winning submission coming just 24 minutes before the conclusion of the nearly three-year-long contest.  Historically the Leaderboard has only reported team scores on the quiz subset. The Prize is awarded based on teams’ test subset score. Now that the contest is closed we will be updating the Leaderboard to report team scores on both the test and quiz subsets.

To everyone who participated in the Netflix Prize: You’ve made this a truly remarkable contest and you’ve brought great innovation to the field. We applaud you for your contributions and we hope you’ve enjoyed the journey. The Netflix Prize contest is now closed.

We will soon be launching a new contest, Netflix Prize 2. Stay tuned for more details.

The winning team’s papers submitted to the judges can be found below.  These papers build on, and require familiarity with, work published in the 2008 Progress Prize.

Y. Koren, “The BellKor Solution to the Netflix Grand Prize”, (2009).

A. Töscher, M. Jahrer, R. Bell, “The BigChaos Solution to the Netflix Grand Prize”, (2009).

M. Piotte, M. Chabbert, “The Pragmatic Theory solution to the Netflix Grand Prize”, (2009).

Congratulations  BellKor’s Pragmatic Chaos.

For all of us – here’s to Netflix Prize 2…:

Netflix Prize 2 focuses on the much harder problem of predicting movie enjoyment by members who don’t rate movies often, or at all, by taking advantage of demographic and behavioral data carrying implicit signals about the individuals’ taste profiles. As with the first Netflix Prize, the sequel will also be an open competition with winning teams owning their solution to license to Netflix and other companies. Success in this problem will enable businesses to deliver superior service to new customers much sooner in their lifecycle, without requiring or waiting for the customer to provide the rich data points that underpinned the first Netflix Prize.

The new data set, providing more than 100 million data points, will include, among other things, information about renters’ ages, genders, ZIP codes, genre ratings and previously chosen movies. As with the first Netflix Prize, all data provided is anonymous and cannot be associated with a specific Netflix member.

Unlike the first challenge, this contest has no specific accuracy target. In fact, Netflix said today that the company and the judges have little idea how far the world’s foremost experts can push this data to derive useful predictions. Instead, $500,000 will be awarded to the team judged to be leading after six months and an additional $500,000 will be given to the team in the lead at the 18-month mark, when the contest is wrapped up. Once again, Netflix will require the winning team to publish its methods.

The Netflix recommendation engine spans the 100,000 DVD titles in the Netflix catalog and is an essential element of the company’s movie subscription service. Each of the 10.6 million Netflix members enjoys a personalized member Web site that enables them to rate movies on a one to five star scale. Netflix combines those individual ratings into a database of more than three billion movie ratings and employs proprietary algorithms and software to identify movies that tend to be rated highly (or poorly) by people with similar tastes. Netflix has already enhanced these algorithms using innovations from the winners of two annual Netflix Progress Prize awards. The accuracy of this software has been praised by movie critics and members alike and enables Netflix to fulfill its goal of connecting people with movies they’ll love.

Complete details about the Netflix Prize are available at www.netflixprize.com.

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Tags: netflix, martin, prize contest, team, statisticians, unpaid volunteer, koren
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Netflix, its Algorithm, My Neighbors, and Me.

July 26th, 2009

I still haven’t quite figured out how Netflix’s business model keeps it profitable - even with a paid subscriber base of 10,000,000, there are a lot of operational costs behind Netflix.com, from software engineering to shipping costs to and from that paid subscriber base; each queued title shipped as a DVD or BluRay disk includes a postage paid return envelope.

Thankfully, Netflix’s business model does work.  My best guess is Netflix’s “typical” customer is not as avid a consumer of the over 90,000 titles in its library as are Mark and I.

We’re also big fans of Netflix’s “Watch Instantly” option, which no doubt cuts down on Netflix’s shipping costs and allows us to simultaneously watch movies together even when stuck on opposite coasts.  As an added bonus, “Watch Instantly” is very eco-friendly. Hopefully Netflix will soon solve whatever licensing or other challenges limit this viewing option to approximately 12,000 titles.

Netflix’s current prediction algorithm led us to movies which have become new favorites, including Outsourced.  It’s also interesting to compare “most popular titles” in our shared residences in the Pacific Northwest and in the Shenandoah Valley.  According to Netflix, the top four titles uniquely popular with our neighbors in suburban Seattle are “Ducktales, Vol.1,” “Rab Ne Bana Di Jodi,” “Om Shanti Om,” and “Mansfield Park;” while the top four picks of our neighbors in the the Shenandoah Valley are “Gilmore Girls: Season 1,” “Deadwood: Season 2,” ”The Last Sin Eater,” and “Nature’s Most Amazing Events.”

It’s been very interesting following Netflix’s crowdsource contest to develop a customer-centric prediction algorithm “which substantially improves  the accuracy of predictions about how much someone is going to love a movie based on their movie preferences.”

Wired covered this competition several times, in February 2008 and last month, in June 2009; TechCrunch much more frequently, as do other websites and bloggers.

Today on TechCrunch:

The Netflix Prize Comes To A Buzzer-Beater, Nailbiting Finish

by Jason Kincaid on July 26, 2009

Who knew statistical computing competitions could be so cut throat? Since we reported on the contest last night, two teams in the Netflix Prize have spent the last few hours jumping back and forth on the Netflix leaderboard as the three-year-long competition ticked into its final moments, with last minute sniping submissions coming from both sides. Finally, the results are in: The Ensemble has managed to come from behind to upset BellKor’s Pragmatic Chaos with a top submission of 10.10% — an improvement of .01% — only 4 minutes before the contest closed.

It’s been a long road to get here. Over the last three years computer science teams around the world have been vying for the Netflix Prize — a competition that invited teams to try to improve on Netflix’s movie recommendation algorithm by 10%, with a reward of $1 million to the best submission. Since then teams have gotten progressively closer to the magical 10% mark, but it wasn’t until last month when a number of top teams joined forces to form BellKor’s Pragmatic Chaos that the barrier was finally broken, with a score of 10.08%. However, their announcement kicked off a 30 day last call period where other teams were invited to make their final submissions.Read More

Then again – the better the algorithm, the bigger the conundrum of “so many options, so little time.”

So – time to move the Roku box I use for “Watching Instantly” into my too rarely used home gym.  While I’m at it, I should make sure the only way I can power the Roku box and TV is by pedaling the stationary bike, or by actually using the eliptical trainer… crowdsource solution, anyone?

Tags: gilmore girls, best guess, teams, deadwood season 2, roku box, contest, subscriber base, prediction algorithm, titles, gilmore girls season
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