Occasionally on AskUbuntu, I've seen highly upvoted answers listed before the accepted answer for a question. This is useful for when the OP accepts a suboptimal or incorrect answer.

However, when does this phenomenon occur? For [some questions](https://askubuntu.com/questions/95336/why-cant-i-update-applications-without-upgrading-the-whole-os/) it clearly doesn't. Is there a mathematical ratio of upvotes vs. downvotes? If so, what is the ratio?