ISO 3951-3:2007规定了双抽样方案的验收抽样系统，用于不合格百分比的变量检验。它根据验收质量限（AQL）编制索引。 ISO 3951-3:2007中规定的方法的目标是确保可接受质量的批次具有较高的验收概率，且不接受劣质批次的概率尽可能高。这是通过切换规则实现的，如果检测到质量恶化，切换规则会自动保护消费者（通过切换到严格检查或停止抽样检查），而且（由负责当局自行决定）降低检验成本的激励（通过切换到较小的样本量）应该始终实现良好的质量。 在ISO 3951-3:2007中，一个批次的可接受性是根据该批次的一个或两个随机样品，通过对过程中不合格项目百分比的估计来隐式或显式确定的。 ISO 3951-3:2007主要设计用于以下条件:检验程序适用于连续系列的离散产品，所有产品均由一个生产商使用一种生产工艺提供；产品项目具有单一质量特征的；质量特性在连续范围内是可测量的；测量误差可忽略不计（即标准偏差不超过相应工艺标准偏差的10%）；生产是稳定的（在统计控制下），质量特性是按照正态分布分布的，至少是近似分布；如果必须选择和检查第二个样品的可能性在管理上是可以接受的；合同或标准对质量特性规定了规格上限、规格下限或两者。 ISO 3951中的程序- 3:2007不适用于之前筛选不合格品的批次。

ISO 3951-3:2007 specifies an acceptance sampling system of double sampling schemes for inspection by variables for percent nonconforming. It is indexed in terms of the acceptance quality limit (AQL). The objectives of the methods laid down in ISO 3951-3:2007 are to ensure that lots of acceptable quality have a high probability of acceptance and that the probability of non-accepting inferior lots is as high as practicable. This is achieved by means of the switching rules, which provide automatic protection to the consumer (by means of a switch to tightened inspection or discontinuation of sampling inspection) should a deterioration in quality be detected, and an incentive (at the discretion of the responsible authority) to reduce inspection costs (by means of a switch to a smaller sample size) should consistently good quality be achieved. In ISO 3951-3:2007, the acceptability of a lot is implicitly or explicitly determined from an estimate of the percentage of nonconforming items in the process, based on either one or two random samples of items from the lot. ISO 3951-3:2007 is primarily designed for use under the following conditions: where the inspection procedure is to be applied to a continuing series of lots of discrete products all supplied by one producer using one production process; where the items of product have a single quality characteristic; where the quality characteristic is measurable on a continuous scale; where the measurement error is negligible (i.e. with a standard deviation no more than 10 % of the corresponding process standard deviation); where production is stable (under statistical control) and the quality characteristic is distributed, at least to a close approximation, according to a normal distribution; where the possibility of having to select and inspect a second sample is administratively acceptable; and where a contract or standard defines an upper specification limit, a lower specification limit, or both on the quality characteristic. The procedures in ISO 3951-3:2007 are not suitable for application to lots that have been screened previously for nonconforming items.