Performance Measures for X Charts with Asymmetric Control Limits

摘要

Theoretical and empirical justification is given for using asymmetric control limits for certain types of production processes. The following are also discussed: the sensitivity of the performance measures to the process and control parameters, the advantages and disadvantages of using asymmetric control limits, and the construction of tradeoff curves to characterize performance. The justification is given in terms of a collection of quantitative performance measures for X charts with asymmetric control limits. The performance measures quantify the false-alarm frequency, the sensitivity to out-of-control conditions, and the resources required for sampling.