Statistical issues in public health monitoring - A review and discussion

Abstract

A review of methods, suggested in the literature, for sequential detection of changes in public health surveillance data is presented. Many authors have noticed the need for prospective methods and there has been an increased interest in both the statistical as well as epidemiological literature on this type of problem in the recent years. However, most of the vast literature in public health monitoring deals with retrospective methods. This is especially apparent dealing with spatial methods. Evaluations with respect to the statistical properties of special interest for on-line surveillance are rare. The special aspects of prospective statistical surveillance as well as different ways of evaluating such methods are described. Attention is given to methods including only the time domain as well as methods for detection where observations have a spatial structure. In the case of surveillance of a change in a Poisson process the likelihood ratio method and the ShiryaevRoberts method are derived.