Control of a production process based on analysis of statistical results is a widely accepted philosophy. However, the role of testing in process control is not fully described. This paper presents a theory of “controlled manufacturing and testing,” where the dual role of a testing station is defined. This is based on two feedback loops: the sorting loop and the process control loop. The concept is extended to a multiple-loop structure comprising the complex operation of a production line. This leads to consideration of optimization of the objective cost function of the control structure. The term of 0% inspection is only applicable to the sorting and not to the process control function of the dual control loops. The novel task is to organize the constant link between the flow of information and its engineering interpretation and corrective action. For this purpose more intelligent process control stations equipped with diagnostic facilities are envisaged.