Consider the manufacture of 5-centimeter-wide gummed labels. Suppose the operation failed to completely cover the back of the label with gum, leaving a 0.6-centimeter-wide gap in the center area. This might never be noticed by the customer--the label would "work" adequately; it might be of interest to the manufacturer as an indication that something was interrupting the smooth flow of the gum and corrective action was required. Now suppose this same- sized gap were located along the edge of the label, leaving it loose at one end so that the envelope to which it was stuck might jam an automatic sorting unit This would likely be evaluated more severely in terms of acceptability, both by the manufacturer and the user. If the manufacturing operation of the gummed labels should happen to be performed with a very wide roll of paper that is coated with gummed material and later slit into 5-centimeter rolls before being cut into individual labels, in those instances where the gap coincided with the slitter setting, a defective product would result.