Graphical evaluation of statistical surveillance

Abstract

A computer program which simultaneously gives graphical information on important characteristics of statistical surveillance methods is presented. Surveillance, that is continual observation of a time series with the goal of timely detection of possible important changes in the underlying process, is used in quality control, economics, medicine and other fields. When surveillance is used in practice it is necessary to evaluate the method in order to know which action is appropriate at an alarm. The probability of a false alarm, the probability of successful detection and the predictive value are three measures (besides the usual ARL), which are illustrated by the program.