Sorting rated items

While shopping on Amazon and Newegg, I've come across a most frustrating problem. Both websites offer a sorting feature where you can view items in a particular category usually by price or name or release date or things like that. Both also allow buyers to rate items after they've used them, and allow potential buyers to sort the items based on other customers' reviews. There is a fairly frustrating problem with this system, however.

Both Amazon and Newegg (and presumably thousands of other online stores) sort by average customer rating when told to sort by rating. If I were shopping for, say, computer monitors on Newegg, and I was looking for one that was reliable and rated highly by a lot of people, the average rating system might be misleading. Say there is an HP monitor for sale, which 500 people bought and liked. One person, however, bought it and found a few dead pixels (manufacturing defect - it happens), and so rated it low. The monitor's average rating would be 4.98 out of 5.00 or something like that.

Now consider a no-name monitor that one person bought and liked. He or she is the only person to have ever rated this monitor, and rated it a 5, making the monitor's average rating 5.00. 5.00 for this no-name monitor is higher than 4.98 for the HP monitor - this would put the no-name monitor higher up on the list if I asked Newegg to sort by "Best rating".

For a selection of two products this seems like a minor problem, but if I were looking for, perhaps, a new DVD burner, the hundreds of products which received two or three 5.00 reviews would fill up many pages of my search with irrelevant products - I would not consider one or two people rating a product a 5.00 to be an accurate indication that the product is, on the whole, reliably constructed. I would have to wade through all those pages before I found the first product rated by more than about five people.

There must be a better way to sort products by customer rating than simply by average rating, which produces misleading results. Newegg's sort by number of ratings is better but still not exactly it. What if five hundred people bought a product and rated it badly? I think a better solution might be some sort of weighted average - 4.98s can be pulled higher than 5.00s if they have more ratings. Something along the lines of (score * number-of-reviews), so that the 500 5.00s that the better product received counts more than the two 5.00s that the inferior product received.


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