Sampling Scheme
Definition
A collection of sampling plans . A sampling plan applies to the sample size based on a specific inspection lot quantity and defines the criteria for determining whether and how a sample is accepted or rejected. In the SAP system, the structure of the sampling plans complies with international standards (for example ISO 2859 and ISO 3951). However, you can also add sampling schemes for different sampling procedures.
Use
You use a sampling scheme if you want to:
Determine the sample size on the basis of the lot size, inspection severity, or combination of inspection severity and AQL (actual quality level)
Store how a decision is made to accept or reject a characteristic
Determine the number of physical samples, based on the lot size, or the number of containers in an inspection lot in sample management
Structure
Valuation Parameters
You can create sampling schemes:
For attributive inspections
For variable inspections based on the s-method
Without valuation parameters, if you use the sampling scheme in a sample-drawing procedure or in a sampling procedure that calls for a sample calculation without a task list
Depending on the valuation parameter used, the sampling plan consists of:
The sample size, acceptance number, and rejection number for attributive inspections
The sample size and K-factor for variable inspections
The sample size if without valuation parameters was specified
Sampling Tables
Depending on whether you work with an AQL value, the sampling scheme contains a sampling plan table (which is arranged according to the lot quantity) for each inspection severity or for each combination of inspection severity and AQL value.
AQL value : Maximum fraction of nonconforming units (as a percentage) or maximum number of defects per 100 units permitted for a lot to be accepted. The AQL (Acceptable Quality Level) is the quality level that represents the upper limit of a satisfactory average quality level for an acceptance sampling inspection.
Inspection severity : in the QM component, the inspection severity serves as an identifier for a normal, reduced, or tightened inspection. By varying the inspection severity, you can flexibly adjust the probability of acceptance and the inspection effort, based on different quality situations. The inspection severity is closely connected to the inspection scope. If all other conditions remain the same, different inspection severities lead to different inspection scopes or acceptance conditions. You can only enter inspection severities that were defined in Customizing.