Presenting the Probabilities of Different Effect Sizes: Towards a Better Understanding and Communication of Statistical Uncertainty

Abstract

How should social scientists understand and communicate the uncertainty of statistically estimated causal effects? I propose we utilize the posterior distribution of a causal effect and present the probability of the effect being greater (in absolute terms) than different minimum effect sizes. Probability is an intuitive measure of uncertainty for understanding and communication. In addition, the proposed approach needs no decision threshold for an uncertainty measure or an effect size, unlike the conventional approaches. I apply the proposed approach to a previous social scientific study, showing it enables richer inference than the significance-vs.-insignificance approach taken by the original study. The accompanying R package makes my approach easy to implement.