Abstract
We would like to provide ideas about multiplicity from the practical point of view of a statistician in a pharmaceutical company. We think that a trial statistician should satisfy not only the requirements, described in ICH-E9, but should also be responsible for explaining statistical analyses, which may be complicated, to non-statisticians in simple language. In addition, certain multiple comparison methods that have been recently developed are hard to understand even for statisticians dealing with clinical trials. When these methods are applied to clinical trials, it is almost impossible to understand the essence of the multiple comparisons and interpret the results correctly. Therefore it is essential to plan a simple confirmatory clinical trial that can be interpreted clearly.
