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Not true - from current leaders of netflix prize: Our experiments clearly show that once you have strong CF models, such extra data is redundant and cannot imp
by gaika 19y ago
Not true - from current leaders of netflix prize:
Our experiments clearly show that once you have strong CF models, such extra data is redundant and cannot improve accuracy on the Netflix dataset.
http://glinden.blogspot.com/2008/03/using-imdb-data-for-netflix-prize.html http://glinden.blogspot.com/2008/03/using-imdb-data-for-netf...
- greendestiny 19y agoThe students used a simple algorithm and got nearly the same results as the bellkor team. So the extra data isn't redundant if it enables a simpler algorithm to perform as well as a more complicated one, even if the complicated algorithm gets no benefit from the extra data.
- gaika 19y agoWould you, as a human, prefer a model that gives you accurate predictions with less data, or a model (that is simpler) but needs more data to be accurate? How is an algorithm any different?
- greendestiny 19y agoWell put it this way, to get good predictions without a lot of data takes a whole team of researchers at bell labs working on this for over a year, with data its a student project.
- timr 19y agoThat's a red herring, and here's why: simpler models take less data to train. Every orthogonal parameter that you add to a statistical model expands the probability space of that model exponentially. If you keep the amount of training data fixed, but keep adding parameters, you'll very quickly arrive at a point where your model will fit your training data exceptionally well, but the result will be meaningless, because you've over-fit your data. Now, I suppose you could make the case that new models are occasionally discovered that allow for more efficient uses of existing data. However, this is a decidedly rare event. Most of the time, gains are made in exactly the way the author suggests -- by adding new sources of data to well-established techniques.
- mhb 19y agoWhat's the name of the student team and what was their result?
- elq 19y agobingo... I've talked to Yehuda and he does know what he's talking about. Given that he works for Bell Labs, it might be within the realm of possibility that he actually tried using movie metadata. If those students have actually come close to BellKor's score, they should submit their qualifying set - Yehuda already has a 9.05% improvement.