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Psychologist Beating Math Nerds in Race to Netflix Prize

Journal written by s1d (1185389) and posted by Zonk on Tue Mar 04, 2008 10:19 PM
from the must-calculate-harder dept.
Programming Math The Internet IT Technology
s1d writes "An almost-anonymous British psychologist named Gavin Potter has suddenly risen to the top of the Netflix prize charts. With his very first attempt, he got a score which took the BellKor team seven months to reach. Currently at a score of 8.07, he has only five teams ahead of him now in the race for the ultimate Netflix algorithm. 'Potter says his anonymity is mostly accidental. He started that way and didn't come out into the open until after Wired found him. "I guess I didn't think it was worth putting up a link until I had got somewhere," he says, adding that he'd been seriously posting under the name of his venture capital and consulting firm, Mathematical Capital, for two months before launching "Just a guy." When he started competing, he posted to his blog: "Decided to take the Netflix Prize seriously. Looks kind of fun. Not sure where I will get to as I am not an academic or a mathematician. However, being an unemployed psychologist I do have a bit of time."'"
+ -
story

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[+] News: Build a Better Netflix, Win a Million Dollars? 197 comments
An anonymous reader writes "In a quest to better movie recommendations, Netflix is opening their database (nytimes, registration and first child required) to users to try to craft a better recommendation technology. The problem is not easy. Says one researcher: 'You're competing with 15 years of really smart people banging away at the problem.'" Recommender systems are really an interesting problem, and that is likely very interesting data to play with.
[+] Netflix Prize Competitor Already Beats Netflix 174 comments
Baldrson writes "Within the first week of the announcement of The Netflix Prize a team has already beaten Netflix's own movie recommendation algorithm. This is pretty impressive given the previously quoted researcher who said: 'You're competing with 15 years of really smart people banging away at the problem.' The team is WXYZConsulting.com apparently registered by a data mining professor named Yi Zhang. Congratulations are in order for Netflix and Prof. Zhang's team who are demonstrating, yet again, the power of prizes to accelerate progress."
[+] Close but no Cigar for Netflix Recommender System 114 comments
Ponca City, We Love You writes "In October 2006, Netflix, the online movie rental service, announced that it would award $1 million to the first team to improve the accuracy of Netflix's movie recommendations by 10% based on personal preferences. Each contestant was given a set of data from which three million predictions were made about how certain users rated certain movies and Netflix compared that list with the actual ratings and generated a score for each team. More than 27,000 contestants from 161 countries submitted their entries and some got close, but not close enough. Today Netflix announced that it is awarding an annual progress prize of $50,000 to a group of researchers at AT&T Labs, who improved the current recommendation system by 8.43 percent but the $1 million grand prize is still up for grabs and a $50,000 progress prize will be awarded every year until the 10 percent goal is met. As part of the rules of the competition, the team was required to disclose their solution publicly. (pdf)"
[+] IT: Anonymity of Netflix Prize Dataset Broken 164 comments
KentuckyFC writes "The anonymity of the Netflix Prize dataset has been broken by a pair of computer scientists from the University of Texas, according to a report from the physics arXivblog. It turns out that an individual's set of ratings and the dates on which they were made are pretty unique, particularly if the ratings involve films outside the most popular 100 movies. So it's straightforward to find a match by comparing the anonymized data against publicly available ratings on the Internet Movie Database (IMDb) (abstract on the physics arxiv). The researchers used this method to find how individuals on the IMDb privately rated films on Netflix, in the process possibly working out their political affiliation, sexual preferences and a number of other personal details"
Journal: Psychologist shining over math wizards for Netflix prize by s1d (1185389)
[+] Science: Interest Still High In the Netflix Algorithm Competition 77 comments
circletimessquare brings us an update to the status of the million-dollar Netflix competition to develop a better algorithm for movie recommendations. We've discussed aspects of the competition since it started two years ago, but the New York Times has a lengthy overview of where it stands now. "The Netflix competition is still going strong, with a vibrant, competitive roster of some 30,000 programmers around the globe hard at work trying to win the prize. The Times provides a look at some of the more obsessive searchers, such as Len Bertoni, a semi-retired computer scientist near Pittsburgh who logs 20 hours a week on the problem, oftentimes with the help of his children. There's also Martin Chabbert in Montreal: 'After the kids are asleep and I've packed the lunches for school, I come down at 9 in the evening and work until 11 or 12.' The article gets into the history of the search algorithm Netflix currently uses, and explores the hot commodity called 'singular value decomposition' that serves as the basis for most of the algorithms in competition."
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Psychologist Beating Math Nerds in Race to Netflix Prize 50 Comments More /

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  • Beating everyone? (Score:5, Funny)

    by Anonymous Coward on Tuesday March 04 2008, @10:22PM (#22645744)
    5th place is not winning. Are you guys Ron Paul supporters too?

      • Re:Beating everyone? (Score:5, Funny)

        by rcw-home (122017) on Wednesday March 05 2008, @12:24AM (#22646406)

        Welcome to your therapy session.

        Well, before everyone gets all in a tizzy,

        Surely not everyone?

        let me just say that I'm already on the case to return the favor.

        Can you elaborate on that?

        As a mathematician and computer scientist, I'm working on a computer program using some pretty heavy-lifting math to allow people to psychoanalyze themselves.

        Why do you mention computers?

        I call it the ELIte analyZing mAchine, or ELIZA for short.

        Why do you mention computers?

        How does that make you feel, Mr. Psychologist Person?

        Does that question interest you?

  • Domain Knowledge (Score:5, Insightful)

    by Anonymous Coward on Tuesday March 04 2008, @10:27PM (#22645772)
    It's called domain knowledge people. It helps being a psychologist when you're write a program reacting to people's behavior. If programmers knew how to do that, they would get laid more.

    • Re: (Score:3, Interesting)

      by Yold (473518)
      Exactly what I thought, even if he is beating math-nerds, you cannot create a machine-learning algorithm without using fairly sophisticated mathematics. Since psychology is largerly based on statistics, I am sure the guy has a firm grounding in the subject. I am sure he isn't basing his algorithm on Aedipus Complexes (sic) and ink blots.

      • Re:Domain Knowledge (Score:5, Funny)

        by wasted (94866) on Tuesday March 04 2008, @11:25PM (#22646116)

        There's a strong social obligation to love sex, just like there's a strong social obligation to hate work. A lot of people love their work and couldn't be bothered wasting their time on mating rituals.. then all the brainless breeders call them "losers" because they've made two choices that fly in the face of social pressure.

        Like they really had a choice...

          • Re: (Score:3, Insightful)

            by LS (57954)
            I don't know who you moderators are or when you got your nuts cut off but I've never felt more cognitive dissonance to a Slashdot post than this one. Every geek I've ever known is dying to get laid but just doesn't have the wherewithal to get it done. Or maybe you, parent poster, are a woman. Calling deadbeat husbands bastards and referring to casual sex as "sport"... hmmmm, I detect that someone may have gotten burned in her past.

          • Re: (Score:3, Funny)

            by nametaken (610866)
            Wow dude, thanks for speaking for me. I was too busy not getting laid to be bothered to type it myself.

  • What's the point? (Score:5, Interesting)

    by causality (777677) on Tuesday March 04 2008, @10:28PM (#22645782)
    Is there some merit to this story other than "your sterotypes can be wrong", which is itself cliche enough to be considered a stereotype in its own right? I like Henry David Thoreau's explanation of such trivia:

    And I am sure that I never read any memorable news in a newspaper. If we read of one man robbed, or murdered, or killed by accident, or one house burned, or one vessel wrecked, or one steamboat blown up, or one cow run over on the Western Railroad, or one mad dog killed, or one lot of grasshoppers in the winter -- we never need read of another. One is enough. If you are acquainted with the principle, what do you care for a myriad instances and applications? To a philosopher all news, as it is called, is gossip, and they who edit and read it are old women over their tea. Yet not a few are greedy after this gossip. There was such a rush, as I hear, the other day at one of the offices to learn the foreign news by the last arrival, that several large squares of plate glass belonging to the establishment were broken by the pressure -- news which I seriously think a ready wit might write a twelve-month, or twelve years, beforehand with sufficient accuracy.


    And yes, I have karma to burn. Yes I do.

      • Re:What's the point? (Score:5, Funny)

        by besalope (1186101) on Wednesday March 05 2008, @12:46AM (#22646518)

        Right. Unless it's your brother that was robbed, your mother's house that burned, your life savings tied up in the boat that sank, your cow that was run down, or your new neighbor's rabid dog that needs killing.
        Meh, that just sounds like the making of a country music hit.

  • Average psychologist (Score:5, Informative)

    by Anonymous Coward on Tuesday March 04 2008, @10:31PM (#22645808)

    that had an undergraduate degree in psychology, a masters degree in operations research [wikipedia.org] that after being well employed for a number of years -- "In 2006, he left his job at IBM to explore the idea of starting a PhD in machine learning, a field in which he has no formal training. When he read about the Netflix Prize, he decided to give it a shot -- what better way to find out just how serious about the topic he really was?"

  • Very few psych majors do psych professional.

    I have a BA from U. of Houston, which I have used to do tech support and sales for a software company, and developed my own FPS as a solo project.

    • That's true (Score:5, Interesting)

      by Crazy Taco (1083423) on Tuesday March 04 2008, @10:56PM (#22645950)

      Very few psych majors do psych professional. I have a BA from U. of Houston, which I have used to do tech support and sales for a software company, and developed my own FPS as a solo project.

      I've also found this to be true. Lol, I actually knew people in college that did nothing but program computers in their spare time, and took psych because it was easy, wouldn't distract them and gave them more time to do the programming they wanted. They didn't ever expect to practice psych.

  • Misleading summary (Score:5, Informative)

    by Zen Programmer (518532) on Tuesday March 04 2008, @10:40PM (#22645856)
    The summary makes 2 references to Gavin Potter being a psychologist, but it ignores the part of the article that notes he has a master's degree in operations research. This is very much an OR problem. Still, it is impressive that he has been able to do as well as he has considering his competition. Good luck to him!

    • Re: (Score:3, Funny)

      by Red Flayer (890720)

      This is very much an OR problem.
      I'm not so sure about that. Seems to me like the Netflix algorithm probably needs some ANDs and NOTs, and maybe even some IF...THENs.

      Not to mention that it likely can't be reduced to Boolean logic.

      /Sorry

  • Interdiscplinary approach (Score:5, Interesting)

    by oceaniv (1243854) on Tuesday March 04 2008, @10:41PM (#22645866)
    The topic is incredibly fascinating. And just a thought, up to 5 centuries ago "scientists" were incredibly versatile people, with mastery over a few fields at a time... A lot of people argue that this was out of necessity, but could the versatility have been important development of multiple renaissances (In Greece, East/West Asia, and Europe)? And could the bottleneck specialization of fields that has occurred in the past three centuries simply be period of transition/stifling new ways of thinking? Could the emergence interdisciplinary experts lead to another 'renaissance' of sorts?

    • Re:Interdiscplinary approach (Score:4, Interesting)

      by Metasquares (555685) <slashdot@@@metasquared...com> on Tuesday March 04 2008, @11:02PM (#22645988) Homepage
      I think so [projectpolymath.org].

    • Re:Interdiscplinary approach (Score:5, Interesting)

      by Kenshin (43036) <kenshin@NospAM.lunarworks.ca> on Tuesday March 04 2008, @11:10PM (#22646034) Homepage
      See, I hate this current mode of profession.

      I work for a small company. My current job isn't stable, and doesn't pay well, so I'm taking an IT course so I can land a (hopefully) stable job/career.

      However... in my current job I wear all kinds of hats. Server's down? I'll fix it. Marketing materials need to be designed? I'll do it. Proposal needs to be edited? I'm there. Computer needs more RAM? I'll install it. Photo of product needs to be masked-out? Done. Need to do some research? I'll get on it.

      The kind of job I'm being trained for... I'll be stuck on the straight and narrow, handling one sort of task. When companies want an IT guy, they want an IT guy. I don't know how I'll be able to handle that. I LIKE having different responsibilities. I don't want to be one guy on an org chart with a specified duty.

      Blah. I really went on a tangent there...

      • Re:Interdiscplinary approach (Score:5, Insightful)

        by mattOzan (165392) < vispuslo AT mattozan DOT net> on Tuesday March 04 2008, @11:37PM (#22646176) Homepage Journal
        I like being jack-of-all-trades too. But I'm finding that one must tread very carefully on this path.

        If you aren't careful, you end up being the fall guy for a widening array of mishaps.

        For instance, you help set up the video projector a couple of times for presentations. Then during the next presentation the projector fails. In some eyes it will be your fault, because you're now the "PowerPoint Guy." Nevermind that the bulb was past its recommended use hours, or that the presenter forgot his VGA dongle, or whatever.

        It seems like if I want to come out as the go-to guy for some area of tech, I'd damn well better get up to pro-level speed really quick. Because soon I'm going to have to be mitigating crises and solving complex problems that before were just chalked up to "well, that thing's always been a problem." Yeah, now it is *your* problem!

      • Re: (Score:3, Insightful)

        by Cylix (55374)
        Surprisingly enough, there are fields that pay much better which require a broad range of expertise.

        However, no one will dare mention all of the real requirements. You see, the valid candidates will run screaming away because it looks to be too much, but what you end up with is a person who scoffs at all the extra that wasn't mentioned when he was hired.

        Thus, eventually the cycle continues until you no longer need the jack of all trades and have many very specialized people who cannot get anything completed

    • WWLD? (What would leonardo do?) (Score:5, Funny)

      by TiggertheMad (556308) on Wednesday March 05 2008, @12:26AM (#22646420) Homepage Journal
      Could the emergence interdisciplinary experts lead to another 'renaissance' of sorts?

      Oh, I don't know. If only we had a art history & statistics dual major to figure it out...

    • Re: (Score:3, Interesting)

      by Antique Geekmeister (740220)
      Or could the existence of things called "printed books" lead to the spread of knowledge among others who could use it, rather than having to build up their theoretical knowledge from personal experience and a few precious manuscripts? And make it more broadly available so that people with less than mutant brilliance can contribute andn publish their contributions for others?

      I don't think you need to read in any great cultural change to a cross-disciplinary approach here: the problem is one well-suited to th

      • Re:Uh, no... (Score:5, Insightful)

        by Anonymous Coward on Tuesday March 04 2008, @11:55PM (#22646268)
        What a bunch of drivel. Just because their level of knowledge isn't what we have today, doesn't make it any "easier." Do you have any idea at all, or can you even comprehend, the kind of mathematics that were employed back in the day to solve anything? Take a look at the Principia for example. The geometry is insane. I'm a graduate student in Physics and I can't really follow his proofs.

        Furthermore, because early scientists did not have as much to build on, that makes it all the more difficult. Where was Faraday to get his inspiration on lines of force? What lead Maxwell in the right direction to unifying light with electromagnetism?

        It's great that 3rd graders know about electric circuits. That's the point of scientific progress. That doesn't make the original task trivial in any sense.

        In other words, I hate you.

      • All of 18th century science? Really? (Score:5, Insightful)

        by BorgCopyeditor (590345) on Wednesday March 05 2008, @12:25AM (#22646418)
        OK, how do you solve a cubic? Or grind the lenses for a telescope? Or build a water pump? How do you dress a head wound? Or isolate pure gases? Or calibrate a thermometer?

        If you know how to do all those things, good for you. My point is that a secondary school education in "science" does not by itself provide one with the same understanding as the great scientists who first among all others figured out how to do each of these things.
        • Subjects get so complex and so specialized there HAS to be limits to how many giants a human can climb and still have time enough to become a giant themselves. Abstraction helps to greatly extend this range; the people behind abstractions/simplifications may not be considered giants because they do not produce progress themselves but just facilitate others so they can extend their reach into the unknown.

          There does not appear to be that many 'giant' scientific figures anymore despite the exponential scientif

  • Umm.... (Score:5, Informative)

    by palegray.net (1195047) <philip DOT paradis AT palegray DOT net> on Tuesday March 04 2008, @10:42PM (#22645886) Homepage Journal
    He might be a psychologist, but his venture firm is named Mathematical Captital [mathematicalcapital.com], after all. His partners appear to have advanced degrees involving mathematics.

  • Psychologist? (Score:5, Insightful)

    by Otter (3800) on Tuesday March 04 2008, @10:43PM (#22645890) Journal
    I don't understand why Wired insists on playing along with Potter's pretense of being an "unemployed psychologist". He's a PhD candidate in machine learning, has a masters in operations research, is ex-IBM and Pricewaterhouse, runs a VC firm -- he has plenty of quantitative and computational training and experience, probably more than most of the contestants.

  • Thinking about how people shop (Score:5, Interesting)

    by GregPK (991973) on Tuesday March 04 2008, @10:47PM (#22645912)
    My extensive retail experience says people like to shop by the following methods. Ratings, Genre, Alphabet.

    So, if I was to setup a movie viewing for them. I'd setup something along the lines of a Genre, rating(R,PG-13,G), Alphabet.

    It's kind of a takeoff on my video game organization method that increases sales of video games by 30 percent. I called it ABSRG short for Alphabetize By Section(4 foot section), Rating(M on top T in the middle and E towards the bottom.), Genre(Sports, driving, shoot em up). Please note, this cannot be patented, I already let it go out for more than a year(Started in 1998)and I have the pictures and time notes to prove it.

      • Re: (Score:2)

        by GregPK (991973)
        They might be able to patent it, but they wouldn't be able to enforce it. I've got this on file with Walmart, Circuit City, Fry's, Target, Gamestop. Walmart actively uses it for their POG.

        • Re: (Score:3, Interesting)

          by WK2 (1072560)
          Maybe they can't win a court case, but they could probably get at least 1 mega$ settlement by suing Walmart, Circuit City, Fry's, Target, and Gamestop.

  • Free Idea (Score:5, Interesting)

    by Speare (84249) on Tuesday March 04 2008, @11:25PM (#22646120) Homepage

    Okay, I'm not trying for this prize, but there's one thing about Netflix "recommendations" that bugs me so I'm throwing out this complete freebie of an idea. If it helps someone get a 0.001% improvement to add this ONE little additional check, great.

    I am learning Japanese. I have been watching several hundred Japanese-language movies for the past couple years. I don't watch movies in Greek, Spanish, Turkish, Farsi, Italian, Russian, German, or Hebrew. I did watch Amelie four years ago but that doesn't mean I love French movies. Most of my recommendations are for foreign films, but only a small fraction of those recommendations are for Japanese movies.

    Apparently, Netflix doesn't have a column in their database saying WHAT language a movie uses principally, it just has a flag saying it is not English. It's the only explanation I can see for not checking for such a strong correlation. I admit, I might not be sharing the experience of the most common movie-renting drone in the bunch, but I doubt I'm the only person who has such a lopsided taste in movies. If the language (or alternate soundtrack languages) ARE known in the database, please see if the renter has a bias for movies in a particular language.

      • Re: (Score:3, Informative)

        by justinlee37 (993373)

        Contest participants retain ownership of the code they write, but the winning team must license it (non-exclusively) to Netflix.

  • Poor math nerds... (Score:4, Funny)

    by Gorimek (61128) on Tuesday March 04 2008, @11:40PM (#22646188) Homepage
    Being beaten up is normal for any nerd, but by a Psychologist - that's gotta hurt...

  • Slightly different take... (Score:3, Insightful)

    by zappepcs (820751) on Wednesday March 05 2008, @12:00AM (#22646302) Journal
    Yes, the story is old now (by Internet standards) and no, he's not actually winning. What he did do was make a great leap in the success of his process by using a better group of knowledge for a base to work with. This is neither new or amazing in anyway. The only reason it makes news is that it's so much common sense that the story is told as if he has had some huge breakthrough.

    Even if he only gets to 9.25% I will bet he gets offers to work with AI researchers around the globe. That is, after all, what their stated goal is - more or less. Every programmer knows about the GUI wars, and has read stories about how programmers have trouble writing code or designing web sites that are intuitive for users. If you want to see you code break, put a user on the keyboard and wait a few minutes.

    Just about everything that I do with computers shows me something that could be more impressive or intuitive. Can you say 'click START to shutdown' ? Applying psychology and math to a computer problem is a problem that programmers are faced with all the time, and the industry as a whole fails on this repeatedly. A matter of personal interest, hobby robotics, holds a particular problem that seems simple but is not and demonstrates the scope of the problem with this story. Try to build a small robot that can wander around your house and never get stuck behind the couch, or anywhere else. Even cockroaches can accomplish this, but sophisticated robotics cannot.

    We've all seen people come from nowhere, solve a problem because they looked at it a different way than everyone else based on their experiences. I think that it is about time that we started doing more of this. The biggest problem that I can see thus far is that people don't act like computers, they seldom repeat anything with precision. Can you say manufacturing robot? Everyone of us has personal tastes, and it's usually only when Hollywood tells us what movies are good that we all fall in line. Sure, some 'blockbusters' fail, but they make money because of the hype. When you remove the hype, it falls apart. Picking out what other people like or might like based on a very small data set is a difficult task. Not everyone likes kids or movies for kids. Not everyone likes hollywood-ized cookie cutter movies. The task is daunting at best.

    Apply that thinking to other things, and you can see why some websites work and others do not. Why some software works and why others fail. Should F1 be the help key or F3? Why not CTRL-H? Maybe your preferences for such things differ from mine. What I'm getting at is that predicting what a human will do is not simple. Categorizing movies by story, style, genre etc. is like applying a tag cloud to it and matching the tag hits of one group to your personal tag choices. It kind of works, kind of does not. Either way, it needs to be applied more often. Just today I received a thank you note from the local Honda dealer where I got my seat belt replaced under warranty. I bought the car 15 years ago from the dealer my mother likes, and is two states away from me now. The dealer that send the card is local to me (2 states from my mom) but they sent the card to her, at MY address. Tell me how a human would have done that?

    The basic problem is that we humans accrue various bits of information and make decisions based on that. Our thinking process halts when something 'just doesn't make sense' to what we are doing. Computers don't do that... yet. Perhaps this guy is on to something, but then maybe not. A human would not only ask what other people liked this movie, but also "you really liked that piece of crap?"

    To put the I in AI is going to take a lot of rethinking. Simply acting like a perfect human won't do it. Oh, you liked that movie? yeah, me too, I love the city where it was filmed. -- get a program to do that? That oddball out-of-left-field thinking is what will make the software very good at predicting what you will or will not like, maybe.

    Have you ever tried to figure out what kind of music someone wou

  • And? (Score:4, Interesting)

    by Secret Rabbit (914973) on Wednesday March 05 2008, @12:19AM (#22646382) Journal
    There a joke that I heard (that's actually pretty much true):

    A Physicist goes to a Mathematician for advise on solving a Differential Equation. The Physicist explains this and writes the equation on a Blackboard. The Mathematician stares at the equation for more than half an hour. Finally, he says, "Yes, it has a solution."

    Basically, the Maths (even applied) are about details and considering them *very* carefully. With this in mind, is it any surprise that they are somewhat "slow"? Especially when they are starting from scratch within the problem domain?
  • The team at the University of Toronto, who are using a neural networks approach, are led by Geoffrey Hinton [wikipedia.org] who has a bachelors degree in experimental psychology.

  • Almost anonymous? (Score:5, Funny)

    by robhiller (757839) on Wednesday March 05 2008, @04:19AM (#22647252)
    Am I the only one that finds the phrase 'An almost-anonymous British psychologist named Gavin Potter' faintly ridiculous?

    • Re:how many GB is the dataset? (Score:4, Informative)

      by Paeva (1176857) on Tuesday March 04 2008, @11:47PM (#22646230) Homepage
      The dataset is about 660MB to download. It unpacks to 2GB of about 18,000 text files.

        • Re:how many GB is the dataset? (Score:4, Informative)

          by Paeva (1176857) on Wednesday March 05 2008, @12:10AM (#22646354) Homepage
          There are 480,189 customers that rated 17,770 movies. The total number of ratings that you're given is 100,480,507. Each user/movie/rating is accompanied by the date of the rating, as well. You then have to submit predictions for the ratings of 2,817,131 additional user/movie combos (they tell you the user, the movie, and the date, and you need to predict the rating). You submit these predictions to Netflix, and they tell you the root-mean-square error between your predictions and the actual ratings that those users gave those movies.

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