[Routine analysis of public health surveillance data: which statistical procedures to use?]

In recent years an increasing interest in epidemiological surveillance (that we prefer to label public health surveillance) has emerged. The viewpoint that the ease of access to computers and statistical software may permit the use of more sophisticated statistical methodologies in the analysis of surveillance data has been profounded in many studies. It is a cause of concern that this attitude, when used indiscriminated by, may lead to analysis lacking in theoretical support. Thus, first, a viewpoint about surveillance in public health is presented and the basic propositions of the theory of statistical hypothesis tests and interval estimation are described briefly and without technicalities. The nature of surveillance data, their nonsampling character and non-random selection are also commented on. Some descriptive procedures that may be used without loss of quality in analysis are described than some procedures that are proposed in the relevant international literature but that need fuller investigation before being introduced in routine data analysis are given.