There are a number of analyses that have been done on strike zone accuracy and consistency and it would be very easy for MLB to coach the lower-performing umps with a goal of improvement in performance. There are other aspects of umpiring that can be assessed, especially in this era of multiple camera angles and extensive use of replay challenges. Which umpires make incorrect calls the most frequently? Which umpires are most often not in correct position to make a call? MLB should negotiate to have measures of performance incorporated into the next collective bargaining agreement with bonuses for the best performers and reassignment to the minor leagues for the laggards. This is long overdue. Edited to add: And seniority should not be part of the formula. You earn the privilege of working in the majors based on performance alone regardless of age or experience.