Rationale: The intent of an SQC Sample is that it will give some information about the specification, without the Cost of Checking more of it. The intent would never be to identify or remove all Defects (even from the Sample, and certainly not from the non-sampled rest of the Document).
1. The observed Effectiveness of the SQC Process is in the range about 30% (or lower) to a maximum of 88%; meaning 70% to 12% of Defects in the area sampled would not be discovered on a single pass of the SQC Process. This Means that even 100% QC of all parts of a specification will still only give us a Sample of all the Defects in the Document.
2. Any form of testing can also use sampling
This Concept entered by Lisa.