Comment 2 for bug 894468

To reverse a quote from Donald Knuth: "Beware of bugs in the above code; I have only tried it, not proved it correct."

The current formula produces results that behave the way we were wanting them to behave: the more ratings there are, the closer they get to their raw mean as opposed to 3.0. <https://wiki.ubuntu.com/SoftwareCenter#top-rated> It's quite possible that it is not exactly correct, and if making it exactly correct does not involve massive computation, certainly we should fix it. So, thanks for posting that question.

I disagree, though, that "ratings are fundamentally ordinal data" necessarily leads to "a mean doesn't make much sense". For example, shoe sizes and off-the-rack dress sizes are ordinal, but it still makes sense to talk about whether the average for either of those is increasing over time. One "Excellent" rating plus one "Terrible" rating does not lead to "Mediocre", but rather "We can't say with any confidence that this is better or worse than mediocre".