The concept of loss function has been combined, with a numerous statistical decision models which require quality cost estimation. Moreover, estimation of the costs of non-conforming product is one of the most important inputs in economic design of control charts. Therefore, on the basis of new Markov chain approach, this paper focused on extending control chart with variable sampling interval by considering the Linex and Taguchi loss functions. This study mainly differs from the others conducted in the field. In that a new approach is offered to achieve closed form of some statistical criteria. Using numerical example, we show that not only the VSI¯X control chart based on the Linex loss function can be more efficient than the VSI¯X control chart based on the Taguchi loss function in terms of the expected cost per hour, but also the percentage improvement in VSI¯X compared to FRS is higher.
