Statistical testing of pre-defined hypotheses is the most important methodology for analysis in comparative clinical trials. With respect to the investigated product, superiority tests versus placebo and non-inferiority tests in comparison with a reference medication are the most common applications.
In contrast, analysis of non-interventional studies (NIS) is mostly carried out by means of descriptive statistical methods (e.g. mean, standard deviation, frequency distributions). Unfairly, descriptive statistics are therefore often considered as “no real statistics” as the results of these methods are not based on p-values.
In this article we would like to address the question whether it is useful to perform statistical testing in the context of a NIS, as it is often requested by the sponsor, and why, if tests are performed, we should handle their results with caution.
The following example should help to understand the point.