On average, Major League Baseball (MLB) umpires behind home plate make correct ball and strike calls about 88% to 90% of the time.
MLB should consider just going with two umps with every crew that rotates behind the plate and those two umps need to be always be above that 90% correct calls.
For incentives to be one of those umps, they should get paid more then the ones on the bases.
This along with the ABS system should greatly improve calls behind the plate