[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...

[rer0tsaz]

To summarize and paraphrase the paper:

> Every upvote should increase the score, every downvote should decrease the score and the more votes there are the less an additional vote should matter. Only "adding pretend votes" satisfies this.

That really puts into words why "adding pretend votes" just felt right to me in practice.