Background: Control charts suggest limits by which a measure is expected to occur if the underlying system, or thing being measured, is performing as it was when the limits were set. Unexpected or improbable readings suggest that a change has happened to the system being measured - ideally the "out of control" data points would trigger an effort to discover the special causes of a quality cost change. For negative measurement changes, you will likely want to eliminate the cause. For positive changes, the cost "owners" may want to implement change the processes to experience that new better state in the future. Once a process or system is changed, new control limits are set to alert those responsible when a new change occurs to the improved process.

As a Management Consultant, I was often frustrated on plant or process tours to see key performance indicator charts posted on production or process "Performance Boards" with no control limits. I would simply ask the owner of the system or process if the change indicated on the chart was good or bad. Some would say positive change is good and negative change is bad.

Question: Do you believe that the quality costs, in each of the prevention cost elements, should be "in control?" State Yes or No and explain why.