What your statistician never told you about P-values

Abstract

We provide a non-technical overview of what P-values are and what they are not. To determine how P-values ought to be used, reported, and interpreted, we must first clarify the often-overlooked differences between, and proper usages of, significance testing and hypothesis testing. Several clinical examples are given to illustrate these differences, and failure to distinguish between them is seen to be problematic. Common misinterpretations of P-values are explained. Confidence intervals provide essential information where P-values are deficient in doing so and they therefore play an essential role in reporting and interpreting study results.