The Unconditional Performance of Control Charts for Zero-Inflated Processes with Estimated Parameters

Control charts for zero-inflated processes have attracted the interest of the researchers in the recent years. In this work we investigate the performance of Shewhart-type charts for zero-inflated Poisson and zero-inflated Binomial processes, in the case of estimated parameters. This is a case that usually occurs in practice, especially prior to starting the process monitoring. Using Monte Carlo simulation we evaluate charts' performance under an unconditional perspective and provide guidelines for their use in practice. We examine both the in-control and the out-of-control performance.