On March 2, NBA commissioner Adam Silver introduced a “comprehensive plan to further strengthen its officiating program,” with one of the key takeaways being that the league will start keeping more advanced analytics and tracking data on their officials.

However, it turns out that the NBA has already been tracking some referee statistics for quite some time. In fact, the play-by-play descriptions on NBA.com, for example, contain statements like “[IND] Turner Foul: Loose Ball (3 PF) (M Kogut)”, and “[WAS] Oubre Jr. Foul: Personal (1 PF) (D Stafford)”.

With a little elbow grease and a lot of data scraping, we can get our hands on these referee statistics early and fairly easily.

Methodology

Generally speaking, there are 13 different types of fouls that the league enters into these play-by-play descriptions.

Shooting, Personal, Defensive 3 Seconds, Loose Ball, Offensive Charge, Shooting Block, Personal Block, Personal Take, Technical, Flagrant Type 1, Flagrant Type 2, and Clear Path.  

With a little extra effort, it’s possible to scrape each referee’s home/away winning percentage, and points scored in their games.  “Personal Take” is the official name for intentional fouls so I threw those out of the data set since they shouldn’t really depend on the referee.  

I also would like to present to you the first “advanced” referee statistics: “Block Charge Ratio,” “Make-Up Calls,” and “Close Game Calls.”

Block Charge Ratio is defined by the following equation: (Personal Block + Shooting Block)/Charges. This should be a useful measure that will indicate whether a ref is more likely to call a block or a charge on those bang-bang plays. More blocks -> higher ratio; more charges -> lower ratio.

Make-Up Calls are defined as a call against a team where the most recent call was against the other team and is within 30 seconds of game time. Granted there are a lot of calls that occur like this that aren’t necessarily make-up calls, but over the course of a season, we should be able to tell which refs are more prone to this type of foul pattern.  

Close Game Calls are foul calls with less than three minutes remaining in the fourth quarter where a game is within five points. A very useful bit of information which could help players decide whether they should try to draw a foul late in games or if the referees are just going to swallow their whistles in tight games.

After turning all the data into per game statistics, I normalized the data and displayed how each referee compared to his peers.  

Without further ado…


John “It’s Going the Other Way” Goble   

Look at all those Offensive Fouls

Scott “Star of the Show” Foster

So many calls

Eric “Against the Grain” Lewis

The favorite ref of away teams everywhere

Haywoode “Steady” Workman

Totally average across the board

Other prominent officials

  

View my full NBA referee database here

Jasper Taylor is a PhD candidate at the University of Hawaii working on his dissertation in Quantum Information and Quantum Simulation. In his spare time, Jasper enjoys applying his data analysis skills with another passion, the NBA. Jasper can be reached at [email protected]