Models and monitoring of zero-inflated processes: The past and current trends

As product quality has increased rapidly in recent years, monitoring and control of products have become more and more difficult. The items were produced with zero defects, and zero-inflated distributions are used to fit the defect count data. Recently, many studies were designed for the estimation and monitoring methods based on the zero-inflated distributions. As zero-inflated models are useful in the modeling of high-yield and rare health-related processes, so, the stated study is designed to provide a summary of past and current trends of monitoring methods under the zero-inflated models. Moreover, a review is done on the several zero-inflated models and their applications in different industries. Finally, some future directions are also highlighted to overcome existing unsolved issues.