Live data from Hacker News

How Not To Sort By Average Rating

evanmiller.org

91–100 of 159 posts

Re: How Not To Sort By Average Rating

#91

While I agree with the spirit of the article, this is one of those cases where a Bayesian treatment is conceptually much clearer. Assume that ratings are being generated by a stable stochastic process where the underlying distribution is multinomial (ignoring the ordinal character of ratings, for the time being) and use a dirichlet conjugate prior. This gives you a posterior distribution over new ratings for an item.…

Here's a paper proposing a solution in that space, and which also compares itself to the article linked here (kind of nice to see... papers sometimes fail to cite stuff that's "only" posted online rather than properly published, even if the authors know about it and it's quite relevant): http://www.dcs.bbk.ac.uk/~dell/publications/dellzhang_ictir2... I emailed Miller a while ago to see what he thought of this reply,…

[deleted]

Re: How Not To Sort By Average Rating

#92

While I agree with the spirit of the article, this is one of those cases where a Bayesian treatment is conceptually much clearer. Assume that ratings are being generated by a stable stochastic process where the underlying distribution is multinomial (ignoring the ordinal character of ratings, for the time being) and use a dirichlet conjugate prior. This gives you a posterior distribution over new ratings for an item.…

Here's a paper proposing a solution in that space, and which also compares itself to the article linked here (kind of nice to see... papers sometimes fail to cite stuff that's "only" posted online rather than properly published, even if the authors know about it and it's quite relevant): http://www.dcs.bbk.ac.uk/~dell/publications/dellzhang_ictir2... I emailed Miller a while ago to see what he thought of this reply,…

I'm too much of a Math idiot to understand that paper. Have you seen a code implementation of it anywhere?

Re: How Not To Sort By Average Rating

#93
post #81

While I agree with the spirit of the article, this is one of those cases where a Bayesian treatment is conceptually much clearer. Assume that ratings are being generated by a stable stochastic process where the underlying distribution is multinomial (ignoring the ordinal character of ratings, for the time being) and use a dirichlet conjugate prior. This gives you a posterior distribution over new ratings for an item.…

I would absolutely love to learn more. I've been trying to solve some novel NLP and machine learning problems lately but my lack of statistical knowledge is becoming apparent the further along I get. Do you have any recommendations for a good introductory treatment of Bayesian statistics?

By far my favorite book on the subject is conveniently available for free on the internet! "Information Theory, Inference and Learning Algorithms" by David MacKay is wonderfully written, well paced and comprehensive. If you like the book, you should purchase a copy, David is a great guy.

http://www.inference.phy.cam.ac.uk/mackay/itila/book.html

Videolectures has some very good videos as well. Zoubin Gharamani has a pretty solid lecture on Bayesian learning at http://videolectures.net/mlss05us_ghahramani_bl/ (he's a great researcher but not the most engaging speaker). Try Christopher Bishop's lecture at http://videolectures.net/mlss09uk_bishop_ibi/ as well, it might be slightly more palatable.

Re: How Not To Sort By Average Rating

#96

Original author here. For the academically inclined, there is a critique of this approach in this paper: http://www.dcs.bbk.ac.uk/~dell/publications/dellzhang_ictir2... Of course, I think the authors miss the point of the algorithm, since I basically wanted a system that is one-sided (i.e. false negatives are OK but false positives are bad). Also, if you deal with more than two outcomes you might be interested in mul…

Mathematician not a statistician...

Would it be reasonable for 5 stars to normalise the data? Should star ratings be on some distribution, for instance?

Re: How Not To Sort By Average Rating

#97

While I agree with the spirit of the article, this is one of those cases where a Bayesian treatment is conceptually much clearer. Assume that ratings are being generated by a stable stochastic process where the underlying distribution is multinomial (ignoring the ordinal character of ratings, for the time being) and use a dirichlet conjugate prior. This gives you a posterior distribution over new ratings for an item.…

Here's a paper proposing a solution in that space, and which also compares itself to the article linked here (kind of nice to see... papers sometimes fail to cite stuff that's "only" posted online rather than properly published, even if the authors know about it and it's quite relevant): http://www.dcs.bbk.ac.uk/~dell/publications/dellzhang_ictir2... I emailed Miller a while ago to see what he thought of this reply,…

(Reply-to-self, too late to edit)

Here are slides from that paper's presentation, for a quicker overview: http://www.dcs.bbk.ac.uk/~dell/publications/dellzhang_ictir2...

Re: How Not To Sort By Average Rating

#98

Original author here. For the academically inclined, there is a critique of this approach in this paper: http://www.dcs.bbk.ac.uk/~dell/publications/dellzhang_ictir2... Of course, I think the authors miss the point of the algorithm, since I basically wanted a system that is one-sided (i.e. false negatives are OK but false positives are bad). Also, if you deal with more than two outcomes you might be interested in mul…

Are we going to see an Nginx module?

Re: How Not To Sort By Average Rating

#99
post #88
post #10

I love it and I hate it. Why I love it: It's precise. It's elegant. It's rigorous. It's based upon solid, proven science & theory. It's a perfect application for a computer. And most of all, it does what's intended: it works. Why I hate it: What human can understand it? I used to implement the first manufacturing and distribution systems that used thinking like this. They figured, "We finally have the horsepower to a…

>What human can understand it? Lets start with Wilson's midpoint, since that's just high school math. def mid(upvotes:Int, downvotes:Int) = { val total = upvotes+downvotes+0.0 val up = upvotes/total val half = 0.5 val a = total/(4+total) val b = 4/(4+total) a * up + b * half } So there are two weights a and b. Using these weights, the midpoint is a weighted average of half and the proportion of upvotes. It should be…

I think the original post still stands - try explaining the above to an irate customer.

Re: How Not To Sort By Average Rating

#100

Original author here. For the academically inclined, there is a critique of this approach in this paper: http://www.dcs.bbk.ac.uk/~dell/publications/dellzhang_ictir2... Of course, I think the authors miss the point of the algorithm, since I basically wanted a system that is one-sided (i.e. false negatives are OK but false positives are bad). Also, if you deal with more than two outcomes you might be interested in mul…

[deleted]
Post reply on HN