Design of single sampling plan by close-form equations

The paper discusses the problem of designing attribute sampling plans by means of closed-form approximate formulae. A methodology is developed to fully characterize the formulae, in terms of design error, i.e. difference between "estimated" and "true" parameters of the sampling plan for given requirements. The focus is on the quality control of isolated lots, but the proposed methodology is applicable to any attribute single sampling plan. The cases in which the design formulae are "exact", and the cases in which they are not, are identified.