Control charts based on order-restricted tests

Control charts are used to monitor process characteristics and to detect changes in process levels. In many situations the deterioration of a process results in process levels that drift monotonically over time. In this paper we use two well-known order-restricted tests to construct new control charts. Simulations are used to compare the new control charts to the exponentially weighted moving average chart. The comparisons show that the performance of the new control charts is similar to that of the EWMA chart.