Multiple P-values and Bonferroni correction.

Most manuscripts submitted to Osteoarthritis and Cartilage include multiple P-values. Many of these manuscripts present multiplicity corrected significance levels. Some of these manuscripts also describe how the correction was performed. Few manuscripts, however, motivate why multiplicity corrections have been performed. Multiple testing is a complex methodological area with potentially grave consequences for mistakes. This is an attempt to briefly explain the basics of the problem.