Abstract: According to an embodiment of the present invention is to provide methods to evaluate the impact of scrapped wafers on the remaining wafers in a lot by using scrap codes and statistical models. An embodiment of the present invention provides a method to obtain a baseline lot population by using cluster analysis model and functional limited yields. The functional limited yields may be for example chain limited yield, dc limited yield, or ac abist limited yield. By utilizing statistical modeling it is possible to determine which failures have an impact on the lot yield and require rework for the lot. In addition by monitoring the impact of failures, it is possible to determine if corrective actions need to be taken for lots that passed through a process prior to correction of the fault.