Comment by albertoleal

Here's a paper that analyzes various ways to rank items using upvotes/downvotes; and comes up with a way to determine which method is the best: http://www.dcs.bbk.ac.uk/~dell/publications/dellzhang_ictir2...

Also related: http://planspace.org/2014/08/17/how-to-sort-by-average-ratin...