Average rating as a measure of "goodness" is wrought with statistical problems. Without the context of other statistical modes, looking at mean is pretty useles

Average rating as a measure of "goodness" is wrought with statistical problems. Without the context of other statistical modes, looking at mean is pretty useless. However, people don't want to look at summary statistics for each item (mean, median, mode, std/var, skew, etc). So we try to come up with scalar metrics that capture "goodness" or "coolness" or whatever. Popularity (how ever you define it) is a common one to use. Here's a good comparison of popularity models: http://blog.linkibol.com/2010/05/07/how-to-build-a-popularity-algorithm-you-can-be-proud-of/ http://blog.linkibol.com/2010/05/07/how-to-build-a-popularit.... In the past I've been pretty happy with "Bayesian average" - it's simple to implement and gives good results. But if you really want to dig into it, you have to consider all kinds of stuff like bimodal distribution of ratings (controversial items), rater quality/consistency, age or ratings, etc, etc. It's really not as simple as you'd think!