Process capability index for Poisson regression profile based on the Spmk index

In many process control applications, the quality of a process or a product can be characterized by a functional relationship between a response variable and one or more explanatory variables which is typically referred to as a profile. Such profiles can be expressed by a linear or a non-linear model. On the other hand, for an in-control process, capability indices are used for process quality improvement. In this article, we propose a method to measure the process capability when the quality of the process is characterized by a Poisson regression profile. The performance of the proposed index is evaluated through simulations studies. Two real data examples illustrate this method.