Note on 'Construction of Double Sampling s-Control Charts for Agile Manufacturing'

摘要

He and Grigoryan (Quality and Reliability Engineering International 2002; 18:343-355) formulated the design of a double-sampling (DS) s control chart as an optimization problem and solved it with a genetic algorithm. They concluded that the DS s control charts can be a more economically preferable alternative in detecting small shifts than traditional s control charts. We explain that, since they only considered the average sample size when the process is in control, their conclusion is questionable.