This is the answer, of course.
There are other things that definitely play into their decision making though that aren't part of any criteria.
Recency bias happens a lot. If one fight clearly wins the first half of a round, but then loses the 2nd half just as clearly as he won the first, then judges almost always seem to give the round to the person who won the later half.
I think a lot of this comes down to just how we are exposed to basic narrative structure all our lives. In movies or books, the climactic moments are not at the start. They can be, but they're not in what's generally considered a good story. They're at the end. We think in terms of beginnings, middles and ends. We want strong endings, and when we get one, it resonates more strongly with us as it's what we expect and are used to.
Body language is another huge factor in how judges are scoring fights. This happens a lot in WMMA, but I've seen fights where a girl has won most of the striking exchanges and had half a round of ground control, but then still lost that round. In all of those cases body language was huge. The other girl would be bouncing around more, would come out of exchanges and jump right back in with more urgency, etc. It seems like a dumb thing, but in fights where things are relatively even, that body language can easily sway judging.