03/06/2019, 16:00 — 17:00 — Abreu Faro Amphitheatre
Manuel Cabral Morais, Instituto Superior Técnico, CEMAT - Universidade de Lisboa
On ARL-unbiased Control Charts
A control chart is a graphical device used to monitor a parameter of a measurable characteristic. An observation of the plotted control statistic beyond the control limits suggests a change in the parameter being monitored. The control limits of most charts tend to be set ignoring the skewness character of the control statistic and this may dramatically affect their average run length (ARL) performance. We derive several ARL-unbiased control charts whose ARL profiles attain a pre-specified maximum when the parameter is on-target. R is used to provide striking illustrations of how ARL-unbiased charts work in practice.