RHB zone: -1.03 < px < 1.00 and (0.92 + batter_height*0.136) < pz < (2.60 + batter_height*0.136)
LHB zone: -1.20 < px < 0.81 and (0.35 + batter_height*0.229) < pz < (2.00 + batter_height*0.229)
2) He then counted the number of called balls and strikes tallied by each pitcher in the borderline zone to get a baseline number of "extra strikes" for each pitcher.
3) He then broke down the data for each pitcher-catcher combination, subtracting off the pitcher's baseline data.
4) Using Dan Turkenkopf's data on the value of switching ball/strike calls, the Runs Saved by each catcher was estimated.
Many more details are in the article, but the results showed that the best catchers for getting extra strikes for their pitchers were: