Some companies especially metal construction, define KPI for their welding process as "keep the monthly rework rate below or equal to 2%". They also present it as a quality objective. They monitor this data monthly and if rate becomes over the 2% they will take corrective actions. Within the 3 year period they tried to keep the rate below 2% and achieved it. When we investigate their rework rate data, observed that sometimes there was increasing or decreasing trends in monthly rework rates but all was below 2%. They stated that they will not take any improvement to decrease this rate or define less rework rate as a target, justify that it may be not achievable.
Question: Is this situation ensure continuous improvement? (the target is rework rate below 2%), if not how can we ensure continuous improvement for welding rework rates? May it quality objective?
What are your opinions?