A shorter examination period and smaller sample sizes are features of this type of plan.
More recently, quality assurance broadened the scope beyond final inspection to include all aspects of manufacturing.
Broader quality management systems include methodologies such as statistical process control, HACCP, six sigma, and ISO 9000.
Sampling provides one rational means of verification that a production lot conforms with the requirements of technical specifications.
Rather than evaluating all items, a specified sample is taken, inspected or tested, and a decision is made about accepting or rejecting the entire production lot.
Plans have known risks: an acceptable quality limit (AQL) and a rejectable quality level, such as lot tolerance percent defective (LTDP), are part of the operating characteristic curve of the sampling plan.
These are primarily statistical risks and do not necessarily imply that a defective product is intentionally being made or accepted.
MIL-STD-105 was a United States defense standard that provided procedures and tables for sampling by attributes (pass or fail characteristic).
The sample size is specified and the basis for acceptance or rejection (number of defects) is provided.