Inappropriate fiddling with statistical analyses to obtain a desirable p-value: tests to detect its presence in published literature.

Abstract

Much has been written regarding p-values below certain thresholds (most notably 0.05) denoting statistical significance and the tendency of such p-values to be more readily publishable in peer-reviewed journals. Intuition suggests that there may be a tendency to manipulate statistical analyses to push a ‘‘near significant p-value’’ to a level that is considered significant. This article presents a method for detecting the presence of such manipulation (herein called ‘‘fiddling’’) in a distribution of p-values from independent studies. Simulations are used to illustrate the properties of the method. The results suggest that the method has low type I error and that power approaches acceptable levels as the number of p-values being studied approaches 1000.