Adam Silver really put his foot in his mouth when commenting about NBA officiating last spring.
He thought this was a positive spin – refs getting 90% of calls correct is pretty good right? No! 90% right means 10% wrong and in the NBA with over 1 officiating call per minute, that translates into 50 calls per game and therefore 5 WRONG CALLS on average per game.
Assuming 2/3 of the wrong calls go in favour of the home team (conservative since officials tend to air on the side of caution and not disappointing the loud crowd), that means a net benefit to the home teams of almost 2 calls per game. 2 extra possessions, 2 extra foul calls, etc. Each possession is worth 1 pt in the NBA, so this is worth 2 pts per game. Doesn’t seem like a lot? Home court in the NBA is ‘only’ worth 3.5 pts and home teams win approx 60% of their games. 2 of the 3.5 points of the home edge is conservatively JUST due to a ref bias that Commissioner Adam Silver just inadvertently admitted.
Next time you are watching your team lose a close one on the road due to a bad call, just know that it is a reality accepted by the Commissioner of the NBA.