With complex products such as automobiles, computers, or major appliances, we usually find
that many different types of nonconformities or defects can occur. Not all of these types of
defects are equally important. A unit of product having one very serious defect would probably
be classified as nonconforming to requirements, but a unit having several minor defects
might not necessarily be nonconforming. In such situations, we need a method to classify
nonconformities or defects according to severity and to weight the various types of defects in
a reasonable manner. Demerit systems for attribute data can be of value in these situations.
One possible demerit scheme is defined as follows.