

One merchant has better reviews. The other has more reviews. - crasshopper
http://www.johndcook.com/blog/2011/09/27/bayesian-amazon

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aculver
I can't remember the last time I had to actually pick between the two, but as
long as the percent of positive reviews is still relatively high (~95%?) I
would tend to go with the one who has more reviews. Seems to me that they'll
be doing more business, therefore their payment, packing and shipping is more
streamlined and I'll receive my item sooner.

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rytis
Which is a shame really. No, I understand that from a customer POV, and I
usually do (did) the same, but now being on the other side of the fence I feel
the pain of all those small just-starting-out e-shops. Can't compete on price
as you're only starting and buying in thousands to get a better price is not
an option. And on top of the suboptimal price they don't have enough reviews.
10-20 good reviews comparing to 100k+ 95%? Yeah, good luck...

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lazyjeff
I don't the beta(1,1) is a good prior. There is not an equal probability
between 0 and 100 that a store has that percentage of good reviews. I think
the the article should recompute the beta parameters using mle over all amazon
stores.

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vacri
High-percentage positive reviews, how I deal with them:

Read the negative reviews. Your answer is there. Positive reviews generally
tell you very little about the product that the product page doesn't already
tell you. Negative reviews are much more informative. If the negative reviews
are only written by mouthbreathers who naysay anything, you know you've
probably got a good product. If your negative reviews start picking up on
issues, especially if they agree, you've got a good indication of the
stumbling blocks.

I've always found negative reviews a lot more informative about the quality
(rather than utility) of a product.

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revorad
I agree. That's why I'm working on summarising reviews as "Common problems
with this product" on my new shopping site.

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shalmanese
Every company building a rating ranking engine needs to understand Bayesian
estimation. The IMDB Top 250 page has an explanation of how they rank at the
bottom of the page: <http://www.imdb.com/chart/top> which shows you a lot of
the methodology without all the math.

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DanBC
The article needs some graphs, or some other visualisations.

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johndcook
You are right. It needed a graph, so I added one this morning.

