Analytics' next step? Tracking refs

Sloan Conference research paper reveals data and trends for NBA referees

Updated: February 28, 2014, 11:35 AM ET
By Kevin Pelton | ESPN Insider

Over the past decade, NBA statistics have made a quantum leap. But as much as we've learned about players and even coaches, the public still knows very little about the other three actors on the court: the referees.

John Ball aims to change that.