Methods and apparatus to predict process quality in a process control system

Method, apparatus and computer program used to predict process quality in a process control system, the method includes receiving process control information relating to a process at a first time including a first value associated with a first measured variable and a second value associated with a second measured variable; determining if a variation based on the received process control information associated with the process exceeds a threshold; if the variation exceeds the threshold calculating a first contribution value based on a contribution of the first measured variable to the variation and a second contribution value based on a contribution of the second measured variable to the variation; determining at least one corrective action based on the first contribution value, the second contribution value, the first value or the: second value; and calculating a predicted process quality based on the at least one corrective action at a time after the first time. Preferably the predicted quality is displayed graphically.