Multiple comparisons in biomedical research: The problem and its solutions

Abstract

One of the most common but rarely discussed problems in Russian biomedical research is a problem of multiple comparisons. When a researcher performs pairwise comparisons of means in several groups the number of tested ststistical hypotheses increases leading to inflation of the alpha-error. In international scientific literature this issue is well-described and several solutions are offered. The aim of this article is to describe the problem of alpha error inflation and present methods for solving the problem of multiple comparisons. The methods suggested in this paper can be applied at the stages of research planning, data analysis and interpretation of the results. Bonferroni, Sidak, Holm-Bonferroni, Holm-Sidak and the Benjamin-Hochberg methods are described in details. We also present user-friendly examples for manual calculations as well as a description of implementation of the suggested solutions using SPSS software.