A process control method for producing acceptable product within a range of acceptable specifications and unacceptable product that are not within the range of acceptable specifications to optimize profit and utilization of resources, the process having at least one input and at least one output that is affected by variation in at least one input, the method including varying the input about a mean of at least one acceptable specification so that the output is optimized to where the revenue from producing one more acceptable unit of product is substantially equal to the cost of producing one more unacceptable unit of product. In another embodiment, a method is provided that includes optimizing a process having inputs and outputs by measuring the inputs and outputs; determining variation of the mean (u.sub.of) and variation about the mean (u.sub.abt); determining causes of u.sub.of; and controlling u.sub.of to match u.sub.abt data values. The method would further include determining the relationship between the output defect rate and changes in inputs, control of u.sub.of; modeling the relationship; and solving for optimum set point of one or more of the inputs. Controlling u.sub.of can include adjusting the inputs, and solving for optimum set point ideally involves utilizing functions for input defect rate, revenue, and cost