Three common misuses of <i>P</i> values

Abstract

"Significance" has a specific meaning in science, especially in statistics. The p-value as a measure of statistical significance (evidence against a null hypothesis) has long been used in statistical inference and has served as a key player in science and research. Despite its clear mathematical definition and original purpose, and being just one of the many statistical measures/criteria, its role has been over-emphasized along with hypothesis testing. Observing and reflecting on this practice, some journals have attempted to ban reporting of p-values, and the American Statistical Association (for the first time in its 177 year old history) released a statement on p-values in 2016. In this article, we intend to review the correct definition of the p-value as well as its common misuses, in the hope that our article is useful to clinicians and researchers.