Khris Middleton's real plus-minus (RPM) may have been the most-cited stat of the Milwaukee Bucks' breakthrough 14/15 season, a fact as encouraging as it was bizarre. Seriously: how often do you get to hear Sidney Moncrief talking about stats derived from ridge regression models?
Novelty aside, Middleton finished the season an impressive 10th in the entire NBA with a +6.1 RPM, which basically means that having Middleton on the court was worth about six points per 100 possessions relative to a league-average player. And yes, that's really, really good. You can read a lot more about what RPM is here and here, though at a high level it's essentially a way to take the raw +/- data you now find in box scores and (using a huge, complicated regression model) strip out the biases that come from playing with different teammates and against opponents of varying quality.