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Meet the Team

The Ensemble was created by a merger between the two teams that appear on the leaderboard as "Grand Prize Team" and "Opera Solutions and Vandelay United".

Gravity Gabor Takacs, Istvan Pilaszy, Bottyan Nemeth, Domonkos Tikk are long time Netflix Prize top competitors from team Gravity and cofounder of Grand Prize Team. They founded the company Gravity which provides high-quality scalable recommendation systems.
Lester Mackey, David Lin, and David Weiss are the members of Dinosaur
, an old school top competitor and cofounder of GPT.
Joe Sill is known as team Expensive Lunch. Joe is GPT's largest shareholder, holding a 16% share prior to the merger which formed The Ensemble. He has a PhD in Computation and Neural Systems from Caltech. Joe can be reached at joe _ sill at yahoo dot com.
Ces Bertino is an embedded systems software engineer. He finished the competition being the third highest ranked single person team. He is also the second highest share holder of the Grand Prize Team, and has been in and out of the top 10 of the leaderboard for a long time.
Dan Nabutovsky is known on the forums as blednotik. He can be contacted at setloed at
William J.J. Roberts developed an elegant algorithm that achieved an RMSE 0f .8907 without any data pre-processing, post-processing, nor blending. You can email him at wrnf2008 at
Wojtek Kulik is a CS graduate, software developer and researcher from Poland.
Willem Mestrom is known as team GreenCircle.
David Purdy ("Charlie Eppes" on the forum) is finishing a PhD in Statistics at UC Berkeley. His dissertation title is "Sparse Models for Sparse Data", and his focus is on the limitations of different methods, ensembles of methods, and visualizations of the model-space.

Opera Solutions is a global consulting company that employs advanced analytics to find superior solutions to data-intensive business problems.  The Opera Solutions’ team   -- Bruce Deng, Peng Zhou, Priyanka Rastog, Arvind Gangadhar, and Jacob Spoelstra – joined together from Opera’s three Analytic Centers of Excellence in San Diego, Shanghai, and New Delhi.  Their collaboration, and their level of performance, is representative of the type of global, world-class expertise Opera brings to bear on its client assignments.

Opera is already successfully applying many of the lessons learned in the Netflix competition to a wide range of business issues.  For example, our Advanced Analytics team has created a powerful predictive engine to help a client in the food business recommend additional products to its customers, driving up sales by 15+%.  For financial services firms, we are successfully applying these techniques in the risk, collections, and fraud prevention areas, beating traditional non-linear models’ performance by substantial margins.  We are also using advanced models and the ensemble techniques we honed in the competition to value real estate portfolios and other investments, to price products, and to develop trading algorithms.

Opera Solutions is headquartered in Jersey City, New Jersey, with offices in New York, London, Paris, San Diego, Shanghai, and New Delhi.

Bill Bame also known as "Clueless" on the Netflix Prize Forums, dabbles in writing, sound design, music composition, software development, artificial intelligence and a variety of other pursuits.
Craig Carmichael is a senior engineer at Lockheed Martin. His hobbies include robotics, theoretical physics, and a good slow chewing of a Twin Bing candy.
Nicholas Ampazis and George Tsagas comprise the Feeds2 team from Greece, named after their personalized RSS aggregator service using recommender system technologies.
Edward De Grijs has developed a low-scoring (that's good!) model with some new techniques.
Chris Hefele is known on the forums as 'Chef-Ele'. By day, he is a systems engineer. By night, he sliced, diced and blended data for our team.
Jeff Howbert (team 'Howbert') likes to read combinatorics texts by the fireplace. Here are his bio and personal website.

Xiang Liang is a machine learning student in China. His blog is located at
Mike Linacre runs the company WinSteps, a company specializing in Rasch analysis and measurement software.
Larry Ya Luo, a.k.a. Dace, became the highest ranked single person player in the contest, and in a remarkably short amount of time.
Greg McAlpin became our de facto team manager and astonished all with his quick decisions and organization.
Aron Miller was happy to participate in the Ensemble's 30 day scramble. He plans on detailing what might be the best single algorithm yet discovered (.8730 or 8.24%). email aroneus at yahoo
Steve Pagliarulo of Team ESP managed to read Kramer's mind and maybe the complexities he unravelled in there is what made him such a good blender.
Bo Yang (known as Newman ! on the leaderboard and forum) has his own method of coming up with ideas. He's a software developer in Vancouver, BC area. His blog has become the standard reference for state of the art of optimizing nearest neighbor models.

Special thanks

Riley Cordova is a graphic designer/new media expert from Denton, TX. He designed this website for The Ensemble. He is also a talented artist, sculptor, and musician.
Clive Gifford had innovative blending methods. Time ran out before The Ensemble was able to take advantage of them.
Susie Murphy has helped The Ensemble by writing, working on the website, coordinating interviews, and many other ways.