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Metadata is in fact useful, though not the metadata that you might expect. One of the biggest wins many teams made was when they started ranking similarity base

Metadata is in fact useful, though not the metadata that you might expect. One of the biggest wins many teams made was when they started ranking similarity based on edit distance of titles.

ambition 18y ago
Edit distance of titles?! Do you have a source? I'm very curious about how and why that would help.
- trevelyan 18y ago
  Indiana Jones and the _______________.
  - akd 18y ago
    "Heat" and "WALL-E" have a shorter edit distance between them than any Indiana Jones movies.
    - jsn 18y ago
      not if you normalize by e.g. minimal string length.
- DaniFong 18y ago
  Here's a paper on the BellKor solution, from one of the top teams: http://research.att.com/~volinsky/netflix/ProgressPrize2007BellKorSolution.pdf http://research.att.com/~volinsky/netflix/ProgressPrize2007B...
  - elq 18y ago
    Yehuda later wrote http://glinden.blogspot.com/2008/03/using-imdb-data-for-netflix-prize.html#c4525777289161540480 http://glinden.blogspot.com/2008/03/using-imdb-data-for-netf... and http://hunch.net/?p=331 http://hunch.net/?p=331 that using movie metadata has produced no measurable improvement in RMSE.
    - DaniFong 18y ago
      The crux of the argument though, is that if you have a strong CF model with many many ratings, you don't seem to get much benefit with their approach (linear combination of models). That doesn't mean that metadata can't be useful with a different approach. It also doesn't mean that metadata isn't useful for sparse data: in fact, it's incredibly useful, because you don't have much of anything else.
      - elq 18y ago
        I cannot dispute that metadata can be useful. But it appears, at least for prediction tasks similar to the prize, that an ounce of weak or strong explicit user input is worth a ton of rich implicit data (including item metadata).
elq 18y ago
levenshtein distance for predictions? haha. I'd be really curious to know which teams in particular use movie metadata? Yehuda Koren (the first commenter in the blog post) has explicitly stated many times that in his humble opinion movie titles and any non-explicit info has been useless. BellKor, BigChaos, Gravity, and Gavin Potter (just a guy in a garage) are going to be presenting at Yehuda's KDD workshop next week. I'm sure other teams will also be represented. I'll ask them if they use movie metadata, and I'm pretty sure the answer will be no.

Metadata is in fact useful, though not the metadata that you might expect. One of the biggest wins many teams made was when they started ranking similarity based on edit distance of titles.

ambition 18y ago

Edit distance of titles?! Do you have a source? I'm very curious about how and why that would help.

trevelyan 18y ago
Indiana Jones and the _______________.
- akd 18y ago
  "Heat" and "WALL-E" have a shorter edit distance between them than any Indiana Jones movies.
  - jsn 18y ago
    not if you normalize by e.g. minimal string length.
DaniFong 18y ago
Here's a paper on the BellKor solution, from one of the top teams: http://research.att.com/~volinsky/netflix/ProgressPrize2007BellKorSolution.pdf http://research.att.com/~volinsky/netflix/ProgressPrize2007B...
- elq 18y ago
  Yehuda later wrote http://glinden.blogspot.com/2008/03/using-imdb-data-for-netflix-prize.html#c4525777289161540480 http://glinden.blogspot.com/2008/03/using-imdb-data-for-netf... and http://hunch.net/?p=331 http://hunch.net/?p=331 that using movie metadata has produced no measurable improvement in RMSE.
  - DaniFong 18y ago
    The crux of the argument though, is that if you have a strong CF model with many many ratings, you don't seem to get much benefit with their approach (linear combination of models). That doesn't mean that metadata can't be useful with a different approach. It also doesn't mean that metadata isn't useful for sparse data: in fact, it's incredibly useful, because you don't have much of anything else.
    - elq 18y ago
      I cannot dispute that metadata can be useful. But it appears, at least for prediction tasks similar to the prize, that an ounce of weak or strong explicit user input is worth a ton of rich implicit data (including item metadata).

elq 18y ago

levenshtein distance for predictions? haha. I'd be really curious to know which teams in particular use movie metadata? Yehuda Koren (the first commenter in the blog post) has explicitly stated many times that in his humble opinion movie titles and any non-explicit info has been useless. BellKor, BigChaos, Gravity, and Gavin Potter (just a guy in a garage) are going to be presenting at Yehuda's KDD workshop next week. I'm sure other teams will also be represented. I'll ask them if they use movie metadata, and I'm pretty sure the answer will be no.