On Application of Generalized Poisson and Compound Distribution in Control Charts for Number of Defects Per Unit

The Poisson distribution, in general remains sensitive to small departure of frequencies especially at the right tail of the distribution. In many situations it may happen that the Generalized Poisson Distribution (GPD) or a compound distribution provides a closer fit to a frequency distribution compared to the usual Poisson distribution. The article examines the possibility of using the GPD and the compound distribution as alternative models to construct the control chart for number of defects per unit (c-chart)