Umpire concussions and working the slot

I had a discussion with one of my umpire buddies at a clinic once and he told me that rather than work the slot, he uses the catcher as a shield and follows him. I told him he was going to get hit by foul tips -- a LOT and HARD!! He said he never gets hit. I called BS!! It's nice to know I have a documented study to fall back on instead of relying on just empirical evidence and my own experience.

Major league did a study on foul balls and the probability of the umpire getting hit by the ball. They designated certain areas as "hot" zones for potential concussions from foul tips. MLB defines the zones as Green Zone, Yellow Zone and Red zone (or Danger Zone). 

The study illustrates why it is safer for umpires to work the slot. The probability of getting hit by a foul ball increases the more you move from the slot. 

If you are an umpire that likes to set up directly behind the catcher, you stand a greater chance of receiving a blow by a foul ball if you follow him when he moves. The same is true for the umpire that moves with the catcher when he sets up outside. The more the catcher moves toward the outside corner the greater chance the umpire has to get hit.