It's not something that can be quantified with a statistic.
But, for whatever reason, when a game is on the line, some teams just seem to have a knack for making the right play at the right time.
in other words, some teams find a way to win. other teams don't find a way to win - or they find a way to lose.
I don't know if it's something that can be coached or taught. I have a feeling it's more of an innate quality - where you either have it or you don't.
and some teams seem to find it one season, and lose it the next season.
that is a big part of why sports are so much fun.