scope:

This part of ISO 14253 expands the scope of decision rules to industrial situations where the default rule of ISO 14253-1 might not be economically optimal.

NOTE 1 ISO 14253-1 provides a default decision rule having a very high probability that a measured value resulting in product acceptance also yields a product with the corresponding measurand conforming to specifications.

NOTE 2 Changing the decision rule from the default case to a more task-specific case requires agreement between the two parties.

This part of ISO 14253 does not address how to determine the cost of correct decisions (accepting conforming workpieces or rejecting nonconforming workpieces) or incorrect decisions (rejecting conforming workpieces or accepting nonconforming workpieces) as this is a business concern. However, the terminology and requirements to communicate and implement the particular decision rules desired by an organization are provided along with examples to guide the reader.

NOTE 3 The decision rules in this part of ISO 14253 pertain to a single metrological characteristic under consideration. Unless otherwise stated, all probability distributions discussed in this document are Gaussian and centrally located and the cost functions are simple step functions; however, the principles of this document can be applied to any probability distribution function or cost function.