Stacked ranking is where a certain percentage fall at the top, a few at the bottom and most in the middle. It is the favorite concept that Bill Gates is pushing to make the schools better. It is a major part of all this Race to the Top crap. If you don't embrace it, you lose funds.
But there's a problem. It doesn't work at Microsoft, where Gates is king.
Forbes points out that it discourages collaboration, which is what I am seeing at my school.