Abstract
This study aims to provide a reliable confidence interval for assessing the process incapability index [C pp ]. The concept of the generalized pivotal quantities is utilized for constructing the generalized confidence interval for [C pp ]. And, simulations are performed for demonstrating our proposed method and one existent method. The results show that the empirical confidences of these two methods are significantly affected by the degree of process departure. Therefore, we suggest the practitioners to select proper one for capability testing purpose based on the information of degree of process departure.