To prevent malfunction or uneven so that performance is based on the same methodology as the basis control. Check the results of work as a basis for training new employees .
To prevent malfunctions or irregular operations, so that it is . According to the same method used as control. Check the others as a basis for training new staff .
to prevent failure or not regularly so the operation is to use the same method as a basis control check the function as the basis of training new employees